System and method for bypassing data from egress facilities

ABSTRACT

An open architecture platform bypasses data from the facilities of a telecommunications carrier, e.g. an incumbent local exchange carrier, by distinguishing between voice and data traffic, and handling voice and data traffic separately. An SS 7  gateway receives and transmits SS 7  signaling messages with the platform. When signaling for a call arrives, the SS 7  gateway informs a control server on the platform. The control server manages the platform resources, including the SS 7  gateway, tandem network access servers (NASs) and modem NASs. A tandem NAS receives the call over bearer channels. The control server determines whether the incoming call is voice traffic or data traffic, by the dialed number, and instructs the tandem NAS how to handle the call. Voiced traffic is transmitted to a switch for transmission from the platform. Data traffic is terminated at a modem NAS, where it is converted into a form suitable for a data network, such as a private data network or an Internet services provider (ISP). The converted data is sent by routers to the data network. The data network need not convert the data, as the function has already been provided by the platform. In lieu of a conversion, the modems can create a tunnel (a virtual private network) between a remote server and the data network.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of application Ser. No.09/196,756, filed Nov. 20, 1998, which application is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates generally to telecommunicationsnetworks and, more particularly, to a system and method for thesignaling, routing and other manipulation of voice and data calls withinthe public switched telephone network.

[0004] 2. Related Art

[0005] Telecommunication networks were originally designed to connectone device, such as a telephone, to another device using switchingservices. Circuit-switched networks provide a dedicated, fixed amount ofcapacity (a “circuit”) between two devices for the entire duration of atransmission session.

[0006] Originally, a circuit was created manually, i.e., by a directconnection from a calling party to a human operator (a “ring down”)along with human cross-connection by the operator to a called party.

[0007] More recently, a circuit is set up between an originating switchand a destination switch using a process known as signaling. Signalingsets up, monitors, and releases connections in a circuit-switchedsystem. Different signaling methods have been devised. Telephone systemsformerly used in-band signaling to set up and “tear down” calls. Signalsof an in-band signaling system are passed through the same channels asthe information being transmitted. Early electromechanical switches usedanalog or multi-frequency (MF) in-band signaling. Thereafter,conventional residential telephones used in-band dual-tone multiplefrequency (DTMF) signaling to connect to an end office switch. Here, thesame wires (and frequencies on the wires) were used to dial a number(using pulses or tones), as are used to transmit voice information.However, in-band signaling permitted unscrupulous callers to use adevice such as a whistle to mimic signaling sounds to commit fraud(e.g., to prematurely discontinue billing by an interexchange carrier(IXC), also known as long distance telephone company).

[0008] More recently, to prevent such fraud, out-of-band signalingsystems were introduced that use, for example, a packet network forsignaling that is separate from the circuit switched network used forcarrying information. For example, integrated services digital network(ISDN) uses a separate channel, a data (D) channel, to pass signalinginformation out-of-band. Common Channel Interoffice Signaling (CCIS) isa network architecture for out-of-band signaling. A popular version ofCCIS signaling is Signaling System 7 (SS7). SS7 is an internationallyrecognized system optimized for use in digital telecommunicationsnetworks.

[0009] SS7 out-of-band signaling provided additional benefits beyondfraud prevention. For example, out-of-band signaling eased quickadoption of advanced features (e.g., caller-id) by permittingmodifications to the separate signaling network. In addition, the SS7network enabled long distance “Equal Access” (i.e., 1+ dialing foraccess to any long distance carrier) as required under the terms of themodified final judgment (MFJ) requiring divestiture of the Regional BellOperating Companies (RBOCs) from their parent company, AT&T.

[0010] While SS7 and other out-of-band signaling systems have advantagesover in-band systems, they still have deficiencies. For example, the SS7network is still more like X.25 rather than a broadband network. Also,SS7 is a limited protocol in that it only addresses setup, teardown, andmonitoring of calls.

[0011] An SS7 network includes a variety of components. Service SwitchPoints (SSPs) are telephone offices which are directly connected to anSS7 network. All calls must originate in or be routed through an SSPswitch. Calls are passed through connections between SSPs within thetelecommunications network. A Signal Transfer Point (STP) is a componentwhich passes signals between SSPs, other STPs, and Service ControlPoints (SCPs) for processing. An STP is a special application packetswitch which operates to pass signaling information. Two STPs may beused together to provide redundancy.

[0012] An SCP is a special application computer which maintainsinformation in a database required by users of the network. SCPdatabases may include, for example, a credit card database for verifyingcharge information or an “800” database for processing toll-free calls.The components in the SS7 network are connected by links. Typically,links between SSPs and STPs can be, for example, A, B, C, D, E or Flinks. Typically, redundant links are also used for connecting an SSPand its corresponding STPs. Customer premises equipment (CPE), such as atelephone, are connected to an SSP or an end office (EO).

[0013] To initiate a call in an SS7 telecommunications network, acalling party using a telephone connected to an originating end office(EO) switch, dials a telephone number of a called party. The telephonenumber is passed from the telephone to the SSP at the originating endoffice (referred to as the “ingress EO”) of the calling party's localexchange carrier (LEC). A LEC is commonly referred to as a localtelephone company. First, the SSP will process triggers and internalroute rules based on satisfaction of certain criteria. Second, the SSPwill initiate further signals to another EO or access tandem (AT), forexample, if necessary. The signaling information can be passed from theSSP to STPs, which route the signals for communication between theingress EO and the terminating end office, or egress EO. The egress EOhas a port designated by the telephone number of the called party. Thecall is set up as a direct connection between the EOs through tandemswitches if no direct trunking exists or if direct trunking is full. Ifthe call is a long distance call, i.e., between a calling party and acalled party located in different local access transport areas (LATAs),then the call is connected through an inter exchange carrier (IXC)switch of any of a number of long distance companies. Such a longdistance call is commonly referred to as an inter-LATA call. LECs andIXCs are collectively referred to as the public switched telephonenetwork (PSTN).

[0014] Emergence of a competitive LEC (CLEC) was facilitated by passageof the Telecommunications Act of 1996, which authorized competition inthe local phone service market. Traditional LECs or RBOCs are now alsoknown as incumbent LECs (ILECs). Thus, CLECs compete with ILECs inproviding local exchange services. A large cost associated with settingup and operating a CLEC is the equipment needed to circuit switch dataand voice calls.

[0015] Since the LECs handle both voice and data communications, largeamounts of information are communicated. Bandwidth concerns are alwayspresent. The PSTN still has deficiencies, particularly with regard todata communications, for such problems as network congestion andbottlenecks.

[0016] The PSTN is ill-equipped to handle the integration of data andvoice communications. Today, data and voice calls are sent through thesame network. Data communications are presently layered on top of voiceswitching.

[0017] Circuit switching is the process of setting up and keeping acircuit open between two or more users, such that the users haveexclusive and full use of the circuit until the connection is released.Packet switching is like circuit switching in that it can also switchinformation between users. Unlike circuit switching, packet switchingdoes not leave a circuit open on a dedicated basis. Packet switching hasconventionally been a data switching technique. Packet switchingseparates a communication into pieces called packets. A packet cancontain addressing information, such as, for example, a destinationaddress. In packet switching, the addresses of a packet are read by aswitch and the packet is then routed down a path toward a switchassociated with the destination address. Different packets can takediverse paths to reach the eventual destination. Typically, in the lastswitching office before the packets reach the destination user, thepackets can be assembled and sequenced.

[0018] A channel, also known as a circuit, is a 64 (Kbps) building blockof T1 series. A circuit is derived from the digitization and coding ofanalog signals. Digitization involves taking 8000 samples per second(i.e., twice the highest voice frequency of 4,000 Hz) for voice traffic.When coded in 8 bit words a 64 Kbps building block is yielded. Thiscircuit is termed a Level 0 Signal and is represented by DS-0 (DigitalSignal at Level 0). Combining 24 of these channels into a serial bitstream using time division multiplexing (TDM) is performed on aframe-by-frame basis. A frame is a sample of all 24 channels (i.e., themultiplicative product of 24 and 8 bits is 192 bits) plus asynchronization bit called a framing bit, which yields a block of 193bits. Frames are transmitted at a rate of 8,000 per second(corresponding to the sampling rate), thus creating a 1.544 Mbps (i.e.,the product of 8,000 and 193 is 1.544 Mbps) transmission rate, which isthe standard T1 rate. This rate is termed DS-1.

[0019] Queuing refers to the act of stacking or holding calls to behandled by a specific person, trunk or trunk group. Queuing theory dealswith the study of the behavior of a system that uses queuing, such as atelephone system. Queuing is very important to the design of packetnetworks where speed of transmission more than offsets the delay ofwaiting for a transmission facility to become available.

[0020] Telephone call traffic is measured in terms of centi call seconds(CCS) (i.e., one hundred call seconds of telephone conversations). Onehour of calling traffic, also known as an Erlang (named after a queuingtheory engineer), is equal to 36 CCS (i.e., the product of 60 minutesper hour and 60 seconds per minute divided by 100, the theoretical limitof a trunk). An Erlang is used to forecast trunking and TDM switchingmatrix capacity. A “non-blocking” matrix (i.e., the same number of linesand trunks) can theoretically switch 36 CCS of traffic. Numerically,traffic on a trunk group, when measured in Erlangs, is equal to theaverage number of trunks in use during the hour in question. Forexample, if a group of trunks carries 20.25 Erlangs during an hour, alittle more than 20 trunks were busy.

[0021] At times of high data traffic, the internal CCS of call trafficof the tandem and egress switches climbs, resulting in such problems asnetwork blocking and busy signals. Data calls traditionally pass throughtandem and egress switches before being switched to a Wide Area Network(WAN) access device. The tandem and egress switches have becomebottlenecks.

[0022] Growth of the Internet has led to increased data communicationstraffic that has exacerbated the problem. Corporations that provideremote modem access to data networks provide dial-up and directconnections. One important example of such corporations are InternetService Providers (ISPs) provide dial-up and direct connection access toInternet subscribers. Dial-up access is based on transmission using theserial line interface protocol (SLIP) or point-to-point protocol (PPP)to the ISP's network access device. An ISP's network access device caninclude a communications server. A communications server represents oneof several devices connected to a local area network (LAN) or wide areanetwork (WAN). A network router can be connected to the LAN. A networkrouter can be, for example, a computer running routing software, or adedicated routing device. The router's serial port is used to provide ahigh-speed communications connection from the ISP to an Internet networkservice provider (NSP).

[0023] Many ISPs are small, start-up companies that face challenges inobtaining the startup capital required to fund large capitalexpenditures required to purchase the data termination and protocolconversion equipment, including routers, communications servers, andracks filled with modems. ISPs must also expend significant sums ofmoney to the ILEC for large numbers of access lines required to passdata calls through tandem and egress switches before being switched toWAN access devices. ISPs must pass on these costs to their subscribers.

[0024] Similarly, a business entity must also invest substantial capitalto purchase communications equipment, when, for example, the entityneeds to provide employees remote access to a private data network.

[0025] The attributes of modem or Internet-type data traffic are verydifferent from those of voice traffic. First, the traffic isqualitatively different. The duration of data traffic (e.g., 20 minutes,12 hours, or more) is typically longer than voice traffic (e.g., 3minutes) and therefore requires different queuing theory. Ironically, adata call often does not even need access to the line all the time sincean Internet call can contain “bursty traffic”, i.e., intermittent burstsof upstream and downstream traffic. Because voice and modem traffic arestructurally different, the probability distribution must be adjustedaccordingly. The statistical distribution for voice calls is an“exponential distribution,” i.e., most calls are 3 minutes or less induration, and there is a rapidly decreasing number of calls lastinglonger than 3 minutes. Data calls (e.g., modem, fax, internet, etc.)have a mean holding time on the order of 20 minutes, and thedistribution of holding times instead of having an exponentialdistribution, has a “power law distribution,” meaning it is notextraordinary to encounter calls of very long duration such as, e.g., 12hours, a day, or even longer.

[0026] Second, modem internet traffic is also quantitatively differentfrom voice traffic. The Internet modem traffic generates much higherloads. Residential lines have been engineered expecting to generateloads of 3 or 4 CCS, and business lines, 5 or 6 CCS. If the samecustomer begins using the same line for Internet traffic, the load caneasily double or triple.

[0027] Today, the public network is optimized for voice. However, modemtraffic has overtaken voice in the local exchange. Queuing theory hasnot been adjusted for this occurrence, resulting in public networkdysfunction. For example, growth in popularity of fixed rate, unlimitedaccess services from ISPs has excessively burdened the PSTNcircuit-switch infrastructure. Each unlimited access connection can tieup a dedicated circuit through a tandem switch and/or an egress endoffice (EO) switch. What is needed then is an improved system forhandling data communications, which would allow data to bypass the localexchange's egress switches and the associated costs from local telephonecompanies.

SUMMARY OF THE INVENTION

[0028] The present invention includes a system implementation and amethod implementation. The system implementation is directed to a systemfor bypassing the egress facilities of a telecommunications system. Thesystem comprises a gateway, a network access server and a controlserver. The gateway communicates with a telecommunications carrier byreceiving and transmitting signaling messages. The network access serverterminates data calls for termination processing and/or forre-originating said data calls. The control server communicates with thegateway for distinguishing between voice calls and data calls receivedfrom the telecommunications carrier and for sending the data calls tothe network access server.

[0029] The gateway communicates with a switch facility in thetelecommunications carrier via the signaling messages. The switch canbe, for example, a class ¾ access tandem switch or a class 5 end officeswitch.

[0030] The gateway can be, for example, a first application programrunning on a host computer; and the control server can be a secondapplication program running on the host computer or on a second hostcomputer. The first application program and the second applicationprogram intercommunicate.

[0031] In one embodiment, the control server has a communicationsportion for communicating with the gateway. The communications portionof the control server and the gateway communicate, for example, via anX.25 protocol format, a transmission control program, internet protocol(TCP/IP) packet format, a user datagram protocol, internet protocol(UDP/IP) packet format. Many other formats are available as well.

[0032] In one embodiment, the control server has a communicationsportion for communicating with a communications portion of the networkaccess server. The communications portion of the control server and thecommunications portion of the network access server communicate via aprotocol such as the network access server (NAS) messaging interface(NMI) protocol (described below) and/or an IPDC protocol (provided in apublically available document, as noted below).”

[0033] In one embodiment, the network access server extends a firstnetwork to a second network by establishing a protocol tunnel for thedata calls. For example, the first network is a virtual private networkand the second network is a data network. The tunnel is establishedusing a point-to-point tunneling protocol (PPTP).

[0034] In an alternative embodiment to the latter, the network accessserver converts the data calls from a first digitized format into asecond digitized format for delivery of the data calls to a destinationdata network. The network access server comprises a first device, thisfirst device terminating the data calls on at least one modem. Forexample, this first device is a modem network access server bay.

[0035] In a preferred embodiment, the first digitized format can be atransmission control program, internet protocol (TCP/IP) packet format,or a user datagram protocol, internet protocol (UDP/IP) packet format,an asynchronous transfer mode (ATM) cell packet format, a point-to-pointtunneling protocol (PPTP) format, a NETBIOS extended user interface(NETBEUI) protocol format, an Appletalk protocol format, a DECnet,BANYAN/VINES, an internet packet exchange (IPX) protocol format, and aninternet control message protocol (ICMP) protocol format. The secondformat can be, for example, a serial line interface protocol (SLIP)protocol format, or a point-to-point (PPP) protocol format. However, thelist of formats that can be used for the first format and the secondformat can be the same.

[0036] The network access server can comprise a second device for timedivision multiplexing the data calls onto the network access server. Thesecond device can be a tandem network access server bay.

[0037] The system can further include a database for distinguishingbetween voice calls and data calls. The database includes a tablecomprising called party numbers and the terminating points correspondingto the called party numbers. If the control server determines that acalled party number corresponds to a data modem, then the call is a datacall.

[0038] In one embodiment, the system further includes a voice switch forswitching the voice calls and for transmitting the voice calls from thesystem.

[0039] The system can be implemented as an open architecture platformthat is leased by or owned by an incumbent local exchange carrier(ILEC), an interexchange carrier (IXC), a competitive local exchangecarrier (CLEC), or an enhanced services provider. In one embodiment, thegateway, control server, network access server, and the voice switch arecollocated. In another embodiment, the gateway, control server, networkaccess server, and the voice switch are in different geographicalregions.

[0040] The method implementation of the invention is directed to amethod for bypassing data from egress facilities of a telecommunicationscarrier. The method includes establishing a call with the openarchitecture telecommunications system, determining whether the call isa voice call or a data call, and terminating the call onto a networkaccess server for termination processing if the call is a data call.

[0041] The step of establishing a call with the telecommunicationssystem includes receiving signaling information to set up a call cominginto the open architecture telecommunications system, informing acontrol server that a call has arrived on the open architecturetelecommunications system, and receiving the call at theopen-architecture telecommunications system. The step of receivingsignaling information comprises receiving signaling information at agateway. In one embodiment, signaling system 7 (SS7) signalinginformation is received at the gateway.

[0042] The step of determining whether the call is a voice call or adata call includes using a telephone number of a called party todetermine whether the call is a voice call or a data call. The telephonenumber can be, for example, a number used to access at least one networkdevice of an Internet Services Provider (ISP), at least one networkdevice of a competitive local exchange (CLEC) carrier, or a customerpremises equipment (CPE).

[0043] In one embodiment, the step of terminating the call onto anetwork access server for termination processing includes converting thecall from a first protocol to a second protocol. The first protocol caninclude, for example, a transmission control program, internet protocol(TCP/IP) packet format, or a user datagram protocol, internet protocol(UDP/IP) packet format. The second protocol can be the same formats aswell, though the second format is preferably different than the firstprotocol format.

[0044] In another embodiment, the step of terminating the call onto anetwork access server for termination processing includes providing aprotocol tunnel from a first network to a second network. Here, it ispossible to use a virtual private network protocol to extend the firstnetwork to the second network. The virtual private network protocol canbe, for example, a point-to-point tunneling (PPTP) protocol. The firstnetwork can be a virtual private network, whereas the second network canbe a data network.

[0045] The terminating step can further include terminating the call toa voice switch if the call is a voice call. The voice switch will switchand transmit the call.

[0046] The present invention provides a number of important features andadvantages. First, the open architecture telecommunications system (orplatform), employing SS7 signaling and open architecture protocolmessaging, uses application logic to identify-and direct incoming datacalls straight to a terminal server. This permits the bypassing of avoice switch entirely. This results in significant cost savings for anentity (such as an ISP, an ILEC, or a CLEC) providing service, ascompared to the conventional means of delivering data calls through theILEC. This decrease in cost results partially from bypass of the egressILEC end office switch for data traffic.

[0047] A further advantage for ISPs is that they are provided data inthe digital form used by data networks (e.g., IP data packets), ratherthan the digital signals conventionally used by switched voice networks(e.g., PPP signals). Consequently, they need not perform costly modemconversion processes that would otherwise be necessary. The eliminationof many telecommunications processes frees up the functions that ISPs,themselves, would have to perform to provide Internet access.

[0048] By separating voice and data traffic, and circuit-switching onlythe voice traffic through a traditional switch (e.g., a NORTEL DMS 500),the CLEC can use a smaller voice switch, decreasing the capital expenseit must pass on to its customers (including ISPs). Thus, it becomes lessexpensive for the ISPs to route data traffic through a CLEC.

[0049] By differentiating between or separating the voice and datatraffic on a single platform, different types of traffic can beoptimally routed. Thus, for example, video traffic being transportedover a modem, can be more efficiently routed over an appropriate carrierrather than through a dedicated circuit switched line.

[0050] The open architecture telecommunications system can virtuallyhandle an infinite number of data modem traffic destined for Internetservice providers (ISPs). This system is scalable by using fewerintelligent network access devices than conventionally used. The presentinvention obviates the need to purchase additional circuit switchinghardware to support switching of data traffic.

[0051] The open architecture telecommunications system also enables theuse of a modem pool at, for example, a CLEC. This is advantageous to theISPs, or business entities owning private data networks, because itoffloads complex functions from ISPs to a specialized platform (alsoknown as a Network Service Provider (NSP)) and redistributes capitalexpenditures to the CLEC NSP. The CLEC NSP often has better access toinvestment capital than would an ISP. The CLEC NSP also benefits fromeconomies of scale by servicing multiple ISPs with a large pool ofmodems.

BRIEF DESCRIPTION OF THE FIGURES

[0052] The present invention will be described with reference to theaccompanying figures, wherein:

[0053]FIG. 1 is a block diagram providing an overview of a standardtelecommunications network;

[0054]FIG. 2 is a block diagram illustrating an overview of a standardtelecommunications network;

[0055]FIG. 3 illustrates a signaling network in greater detail;

[0056]FIG. 4 provides an overview of the present invention in that itprovides an enhanced telecommunications network;

[0057]FIG. 5 illustrates an open architecture platform in detail;

[0058]FIG. 6 illustrates an object oriented or wire line protocol formatOpen Architecture SS7 Gateway application and SS7 adapter communicatingdirectly with lower level libraries;

[0059]FIG. 7 illustrates an object oriented or wire line protocol formatOpen Architecture Control Server application;

[0060]FIG. 8 illustrates an exemplary Network Access Server bay;

[0061]FIG. 9A is a more elaborate view of the present invention;

[0062]FIG. 9B depicts multiple collocated or geographically diverse SS7Gateways, Control Servers, Databases and Network Access Servers;

[0063]FIGS. 10A, 10B and 10C, are flow charts illustrating how anoriginating caller gains access to an open architecture platform;

[0064]FIG. 11 is a flow chart describing how the open architectureplatform handles an inbound call;

[0065]FIG. 12 is a block diagram illustrating a complex outbound call;

[0066]FIG. 13 is a state diagram illustrating NAS side inbound callhandling on the open architecture platform of the present invention;

[0067]FIGS. 14A and 14B are flow charts illustrating a state diagram ofNAS side exception handling;

[0068]FIG. 15 is a state diagram illustrating NAS side release requesthandling;

[0069]FIG. 16 is a state diagram illustrating NAS side release TDMconnection handling;

[0070]FIGS. 17A and 17B are state diagrams illustrating NAS sidecontinuity test handling; and

[0071]FIGS. 18A and 18B are state diagrams illustrating NAS sideoutbound call handling initiated by a NAS for use in callback.

[0072] In the figures, like reference numbers generally indicateidentical, functionally similar, and/or structurally similar elements.The figure in which an element first appears is indicated by theleftmost digit(s) in the reference number.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0073] Table of Contents I. An Example Environment II. Definitions III.Introduction A. An Overview of a Telecommunications Network B. TheSignaling Network IV. The Present Invention A. Overview of Data BypassB. Detailed Description of Data Bypass 1. The Open Architecture Platform2. Data Bypass Operations 3. NAS Bay to GW Communications 4. ControlMessages 5. A Detailed View of the Control Messages a. Startup Messagesb. Protocol Error Messages c. System Configuration Messages d. TelcoInterface Configuration Messages e. Gateway Configuration Messages f.Maintenance-Status (State) Messages g. Continuity Test Messages h.Keepalive Test Messages i. LAN Test Messages j. DTMF Function Messagesk. Inbound Call Handling Messages l. Outbound Call Handling Messages m.Pass-through Call Handling Messages n. Call Clearing Messages 6. ControlMessage Parameters 7. A Detailed View of the Control Messages a. StartupFlow b. Module Status Notification c. Line Status Notification Flow d.Blocking of Channels Flow e. Unblocking of Channels Flow f. Inbound CallFlow (Without Loopback Continuity Testing) g. Inbound Call Flow (WithLoopback Continuity Testing) h. Outbound Call Flow (Starting from theNAS) i. Outbound Call Flow (Starting from the GW) j. Outbound Call Flow(Starting from the NAS, with Continuity Testing) k. TDM Pass-throughCall Request Flow (Inter- switch Connection) l. Call Releasing Flow(from NAS) m. Call Releasing Flow (from GW) n. Complex Outbound CallRequest Flow Example o. Continuity Test Flow p. Keep-alive Test Flow q.Reset Request Flow V. Conclusion

I. An Example Environment{TC\l1″}

[0074] The present invention is described in terms of an exampleenvironment. The example environment uses an open architecture platformfor transmission of voice and data information received from atelecommunications carrier. As used herein, a telecommunications carriercan include domestic entities such as ILECs, CLECs, IXCs and EnhancedService Providers (ESPs), as well as global entities recognized by thoseskilled in the art. In addition, as used herein a telecommunicationssystem includes domestic systems used by such entities as ILECs, CLECs,IXCs and Enhanced Service Providers (ESPs), as well as global systemsrecognized by those skilled in the art.

[0075] In the preferred embodiment, the open architecture platform isimplemented on a SUN Workstation model 450, available from SunMicrosystems, Inc., Palo Alto, Calif. The Sun workstation isinterconnected with tandem network access service (NAS) bays and modemNAS bays and provides signaling and control functions. The tandem NASbays and modem NAS bays can be ASCEND Access Concentrators, model TNT,available from Ascend Communications, Inc., Alameda, Calif. Voicetraffic is received at the tandem NAS bays and routed to a NORTEL DMSswitch, model DMS 500, available from NORTEL, Richardson, Tex. forrouting to a called party.

[0076] Data traffic is received at the tandem NAS bays, and is routed toa modem NAS bay for modem termination, where the data traffic ismodulated from, for example, the point-to-point protocol (PPP) to anauxiliary protocol such as, for example, the internet protocol (IP) forreorigination and transmission to a data network.

[0077] In the alternative, a virtual private networking protocol, suchas the point-to-point tunneling protocol (PPTP), can be used to create a“tunnel” between a remote user and a data network. A tunnel permits anetwork administrator to extend a virtual private network from a server(e.g., a Windows NT server) to a data network (e.g., the Internet).

[0078] Where a conversion does take place, the converted data traffic isrouted, for example, over an Ethernet/WAN (e.g., an Ethernet switch)connection to an internal backbone on the network, and sent to networkrouters for transmission to a data network, such as for example thenetwork of an Internet Service Provider (ISP). Network routers caninclude, for example, a computer, such as the SUN workstation runningrouting software or a dedicated routing device such as various modelsfrom CISCO of San Jose, Calif., ASCEND of Alameda, Calif., NETOPIA ofAlameda, Calif., or 3COM of Santa Clara, Calif.

[0079] Although the invention is described in terms of this exampleenvironment, it is important to note that description in these terms isprovided for purposes of illustration only. It is not intended that theinvention be limited to this example environment or to the preciseinter-operations between the above-noted devices. In fact, after readingthe following description, it will become apparent to a person skilledin the relevant art how to implement the invention in alternativeenvironments.

[0080] The invention provides two functions which those skilled in theart will recognize can be implemented in many ways. The first functionis that the invention bypasses data from the egress facilities used tocomplete a call. This includes, for example, the network nodes orsystems used to terminate a switched voice call to a called party or toterminate a data connection with a data network.

[0081] The second function is that the invention provides fortermination and reorigination of the call. In one embodiment, data isconverted from a first digital form (e.g., in a point-to-point (PPP)digital format) used by the ingress telecommunications services provider(telecommunications carriers including enhanced service providers) to asecond form used by a destination data network (e.g., IP data packets).This function is traditionally performed by the entities controlling thedestination data network (e.g., ISPs).

[0082] In another embodiment, a virtual private networking protocol(e.g., a point-to-point tunneling protocol (PPTP)), can be used tocreate a “tunnel” between a remote user and a data network. The callterminates at the modem and reoriginates from that destination toanother point.

[0083] After having the benefit of reading this disclosure, thoseskilled in the art will recognize that many types of resources, whethercollocated or geographically separated, may be used to perform thesefunctions.

II. Definitions{TC\l1″}

[0084] Table 1 below defines common telecommunications terminology.These terms are used throughout the remainder of the description of theinvention. TABLE 1 Term Definition local exchange LECs are providers oflocal telecommunications carrier (LEC) services. inter-exchange IXCs areproviders of US domestic long distance carrier (IXC) telecommunicationsservices. AT&T, Sprint and MCI are example IXCs. incumbent LEC ILECs arethe traditional LECs, which include the (ILEC) Regional Bell OperatingCompanies (RBOCs). competitive CLECs are telecommunications servicesproviders LEC (CLEC) capable of providing local services that competewith ILECS. A CLEC may or may not handle IXC services as well. localaccess A LATA is a region in which a LEG offers services. and There are161 LATAs of these local geographical transport areas within the UnitedStates. area (LATA) end office An EO is a class 5 switch used to switchlocal calls (EO) within a LATA. Subscribers of the LEG are connected(“homed”) to EOs, meaning that EOs are the last switches to which thesubscribers are connected. central office A CO is a facility that housesan EO homed. EOs (CO) are often called COs. access tandem An AT is aclass 3/4 switch used to switch calls (AT) between EOs in a LATA. An ATprovides subscribers access to the IXCs, to provide long distancecalling services. An access tandem is a network node. Other networknodes include, for example, a CLEC, or other enhanced service provider(ESP), an international gateway or global point-of-presence (GPOP), oran intelligent peripheral(IP). switching An office class is a functionalranking of a telephone hierarchy or central office switch depending ontransmission office requirements and hierarchical relationship to otherclassification switching centers. Prior to divestiture, an officeclassification was the number assigned to offices according to theirhierarchical function in the U.S. public switched network (PSTN). Thefollowing class numbers are used: class 1 - Regional Center (RC), class2 - Sectional Center (SC), class 3 - Primary Center (PC), class 4 - TollCenter (TC) if operators are present or else Toll Point (TP), class 5 -End Office (EO) a local central office. Any one center handles trafficfrom one to two or more centers lower in the hierarchy. Sincedivestiture and with more intelligent software in switching offices,these designations have become less firm. The class 5 switch was theclosest to the end subscriber. Technology has distributed technologycloser to the end user, diffusing traditional definitions of networkswitching hierarchies and the class of switches. class 5 switch A class5 switching office is an end office (EO) or the lowest level of localand long distance switching, a local central office. The switch closestto the end subscriber. class 4 switch A class 4 switching office was aToll Center (TC) if operators were present or else a Toll Point (TP); anaccess tandem (AT) has class 4 functionality. class 3 switch A class 3switching office was a Primary Center (PC); an access tandem (AT) hasclass 3 functionality. class 1 switch A class 1 switching office, theRegional Center(RC), is the highest level of local and long distanceswitching, or “office of last resort” to complete a call. transmissionTCP/IP is a protocol that provides communications control betweeninterconnected networks. The TCP/IP protocol/ protocol is widely used onthe Internet, which is a internet network comprising several largenetworks protocol connected by high-speed connections. (TCP/IP) internetprotocol IP is part of the TCP/IP protocols. It is used to (IP)recognize incoming messages, route outgoing messages, and keep track ofInternet node addresses (using a number to specify a TCP/IP host on theInternet). IP corresponds to network layer of OSI. transmission TCP isan end-to-end protocol that operates at the control transport andsessions layers of OSI, providing protocol delivery of data bytesbetween processes running in (TCP) host computers via separation andsequencing of IP packets. point-to-point PPP is a protocol permitting acomputer to establish (PPP) protocol a connection with the Internetusing a modem. PPP supports high-quality graphical front ends, likeNetscape. point-to-point A virtual private networking protocol,point-to-point tunneling tunneling protocol (PPTP), can be used tocreate a protocol “tunnel” between a remote user and a data network.(PPTP) A runnel permits a network administrator to extend a virtualprivate network (VPN) from a server (e.g., a Windows NT server) to adata network (e.g., the Internet). point of A POP refers to the locationwithin a LATA where presence the IXC and LEG facilities interface. (POP)global A GPOP refers to the location where international point oftelecommunications facilities and domestic facilities presenceinterface, an international gateway POP. (GPOP) bearer (B) Bearer (B)channels are digital channels used to channels carry both digital voiceand digital data information. An ISDN bearer channel is 64,000 bits persecond, which can carry PCM-digitized voice or data. Internet An ISP isa company that provides Internet access to service subscribers. provider(ISP) integrated ISDN is a network that provides a standard for servicescommunications (voice, data and signaling), end-to- digital end digitaltransmission circuits, out-of-band network signaling, and a featuressignificant amount of (ISDN) bandwidth. local area A LAN is acommunications network providing network connections between computersand peripheral (LAN) devices (e.g., printers and modems) over arelatively short distance (e.g., within a building) under standardizedcontrol. private branch A PBX is a private switch located on thepremises of exchange (PBX) a user. The user is typically a privatecompany which desires to provide switching locally. customer CPE refersto devices residing on the premises of a premises customer and used toconnect to a telephone equipment (CPE) network, including ordinarytelephones, key telephone systems, PBXs, video conferencing devices andmodems. wide area A WAN is a data network that extends a LAN overnetwork the circuits of a telecommunications carrier. The (WAN) carrieris typically a common carrier. A bridging switch or a router is used toconnect the LAN to the WAN. public The PSTN is the worldwide switchedvoice network. switched telephone network (PSTN) packetized One exampleof packetized voice is voice over voice or internet protocol (VOIP).Voice over packet refers voice over a to the carrying of telephony orvoice traffic over a backbone data network, e.g. voice over frame, voiceover ATM, voice over Internet Protocol (IP), over virtual privatenetworks (VPNs), voice over a backbone, etc. digitized Digitized datarefers to analog data that has been data sampled into a binaryrepresentation (i.e., (or digital comprising sequences of 0's and 1's).Digitized data data) is less susceptible to noise and attenuationdistortions because it is more easily regenerated to reconstruct theoriginal signal. number NPA is an area code. NXX is an exchange,planning area identifying the EO homed to the subscriber. (The (NPA);NXX homed EO is typically called a central office (CO).) digital accessA DACS is a device providing digital routing and and cross- switchingfunctions for T1 lines, as well as DSO connect system portions of lines,for a multiple of T1 ports. (DACS) modified final Modified finaljudgment (MFJ) was the decision judgment (MFJ) requiring divestiture ofthe Regional Bell Operating Companies (RBOCs) from their parent company,AT&T. equal access 1+ dialing as used in US domestic calling for accessto any long distance carrier as required under the terms of the modifiedfinal judgment (MFJ) requiring divestiture of the Regional BellOperating Companies (RBOCs) from their parent company, AT&T. regionalBell RBOCs are the Bell operating companies providing operating LEGservices after being divested from AT&T. companies (RBOCs) inter machineAn IMT is a circuit between two commonly- trunk (IMT) connectedswitches. network node A network node is a generic term for theresources in a telecommunications network, including switches, DACS,regenerators, etc. Network nodes essentially include all non-circuit(transport) devices. Other network nodes can include, for example,equipment of a CLEC, or other enhanced service provider (ESP), apoint-of-presence (POP), an international gateway or globalpoint-of-presence (GPOP). intelligent An intelligent peripheral is anetwork system (e.g. a peripheral general purpose computer runningapplication logic) in the Advanced Intelligent Network Release 1 (AIN)architecture. It contains a resource control execution environment(RCEE) functional group that enables flexible information interactionsbetween a user and a network. An intelligent peripheral providesresource management of devices such as voice response units, voiceannouncers, and dual tone multiple frequency (DTMF) sensors for caller-activated services. The intelligent peripheral is accessed by theservice control point (SCP) when services demand its interaction.Intelligent peripherals provide an intelligent network with thefunctionality to allow customers to define their network needsthemselves, without the use of telephone company personnel. Anintelligent peripheral can provide a routing decision that it canterminate, but perhaps cannot regenerate. tele- A LEC, a CLEC, an IXC,an Enhanced Service communications Provider (ESP), an intelligentperipheral (IP), an carrier international/global point-of-presence(GPOP), i.e., any provider of telecommunications services. calling partyThe calling party is the caller placing a call over any kind of networkfrom the origination end. called party The called party is the callerreceiving a call sent over a network at the destination or terminationend. ingress Ingress refers to the connection from a calling party ororigination. egress Egress refers to the connection from a called partyor termination at the destination end of a network, to the serving wirecenter (SWC). ingress EO The ingress EO is the node or serving wirecenter (SVC) with a direct connection to the calling party, theorigination point. The calling party is “homed” to the ingress EO.egress EO The egress EO is the node or destination EO with a directconnection to the called party, the termination point. The called partyis “homed” to the egress EO. signaling SS7 is a type of common channelinteroffice system 7 signaling (CCIS) used widely throughout the world.(SS7) The SS7 network provides the signaling functions of indicating thearrival of calls, transmitting routing and destination signals, andmonitoring line and circuit status. centum call Telephone call trafficis measured in terms of seconds (CCS) centum call seconds (CCS) (i.e.,one hundred call seconds of telephone conversations). {fraction (1/36)}of an Erlang. Erlang An Erlang (named after a queuing theory engineer)is one hour of calling traffic, i.e. it is equal to 36 CCS (i.e., theproduct of 60 minutes per hour and 60 seconds per minute divided by100). An Erlang is used to forecast trunking and TDM switching matrixcapacity. A “non-blocking” matrix (i.e., the same number of lines andtrunks) can theoretically switch 36 CCS of traffic. Numerically, trafficon a trunk group, when measured in Erlangs, is equal to the averagenumber of trunks in use during the hour in question. Thus, if a group oftrunks carries 20.25 Erlangs during an hour, a little more than 20trunks were busy. Enhanced A network services provider. Service Provider(ESP) trunk A trunk connects an access tandem (AT) to an end office(EO). inter machine An inter-machine trunk (IMT) is a circuit betweentrunk (IMT) two commonly-connected switches. Private Line A private lineis a direct channel specifically with a dedicated to a customer's usebetween two dial tone specificed points. A private line with a dial tonecan connect a PBX or an ISP's access concentrator to an end office (e.g.a channelized T1 or PRI). A private line can also be known as a leasedline. plain old The plain old telephone system (POTS) line providestelephone basic service supplying standard single line system (POTS)telephones, telephone lines and access to the public switched telephonenetwork (PSTN). All POTS lines work on loop start signaling. One“starts” (seizes) a phone line ortrunk by giving a supervisory signal(e.g. taking the phone off hook). Loop start signaling involves seizinga line by bridging through a resistance the tip and ring (both wires) ofa telephone line. integrated An ISDN Basic Rate Interface (BRI) lineprovides 2 service bearer B channels and 1 data D line (known as digital“2B + D” over one or two pairs) to a subscriber. network (ISDN) basicrate interface (BRI) line ISDN primary An ISDN Primary Rate Interface(PRI) line provides rate the ISDN equivalent of a T1 circuit. The PRIinterface delivered to a customer's premises can provide (PRI) 23B + D(in North America) or 30B + D (in Europe) channels running at 1.544megabits per second and 2.048 megabits per second, respectively. Pipe orA pipe or dedicated communications facility dedicated connects an ISP tothe internet. communications facility

III. Introduction{TC\l1″}

[0085] A. An Overview of a Telecommunications Network{TC\l2″}

[0086]FIG. 1 is a block diagram providing an overview of a standardtelecommunications network 100 providing local exchange carrier (LEC)services within a local access and transport area (LATA).Telecommunications network 100 provides a switched voice connection froma calling party 102 to a called party 110, as well as a data connectionfrom calling party 102 to, for example, an Internet service provider(ISP) 112. Calling party 102 and called party 110 can be ordinarytelephone equipment, key telephone systems, private branch exchanges(PBXs), or applications running on a host computer. ISP 112 can in thealternative be, for example, a private data network. For example,calling party 102 can be an employee working on a notebook computer at aremote location who is accessing his employer's private data networkthrough, for example, a dial-up modem connection.

[0087]FIG. 1 also includes end offices (EOs) 104 and 108. EO 104 iscalled an ingress EO because it provides a connection from calling party102 to public switched telephone network (PSTN) facilities. EO 108 iscalled an egress EO because it provides a connection from the PSTNfacilities to a called party 110. In addition to ingress EO 104 andegress EO 108, the PSTN facilities associated with telecommunicationsnetwork 100 include an access tandem (AT) 106 that provides access toone or more inter-exchange carriers (IXCs) for long distance traffic.Alternatively, it would be apparent to a person having ordinary skill inthe art that AT 106 could also be, for example, a CLEC, or otherenhanced service provider (ESP), an international gateway or globalpoint-of-presence (GPOP), or an intelligent peripheral.

[0088] EO 104 and AT 106 are part of a switching hierarchy. EO 104 isknown as a class 5 office and AT 106 is a class ¾ office switch. Priorto the divestiture of the RBOCs from AT&T, an office classification wasthe number assigned to offices according to their hierarchical functionin the U.S. public switched network (PSTN). An office class is afunctional ranking of a telephone central office switch depending ontransmission requirements and hierarchical relationship to otherswitching centers. A class 1 office was known as a Regional Center (RC),the highest level office, or the “office of last resort” to complete acall. A class 2 office was known as a Sectional Center (SC). A class 3office was known as a Primary Center (PC). A class 4 office was known aseither a Toll Center (TC) if operators were present, or otherwise as aToll Point (TP). A class 5 office was an End Office (EO), i.e., a localcentral office, the lowest level for local and long distance switching,and was the closest to the end subscriber. Any one center handlestraffic from one or more centers lower in the hierarchy. Sincedivestiture and with more intelligent software in switching offices,these designations have become less firm. Technology has distributedfunctionality closer to the end user, diffusing traditional definitionsof network hierarchies and the class of switches.

[0089] Network 100 includes an Internet service provider (ISP) 112. TheInternet is a well-known, worldwide network comprising several largenetworks connected together by data links. These links include, forexample, Integrated Digital Services Network (ISDN), T1, T3, FDDI andSONET links. Alternatively, an internet can be a private networkinterconnecting a plurality of LANs and WANs, such as, for example, anintranet. ISP 112 provides Internet services for subscribers such ascalling party 102.

[0090] To establish a connection with ISP 112, calling party 102 can usea host computer connected to a modem (modulator/demodulator). The modemwill modulate data from the host computer into a form (traditionally ananalog form) for transmission to the LEC facilities. Typically, the LECfacilities convert the incoming analog signal into a digital form. Inone embodiment, the data is converted into the point-to-point protocol(PPP) format. (PPP is a well-known protocol that permits a computer toestablish a connection with the Internet using a standard modem. Itsupports high-quality, graphical user-interfaces, such as Netscape.) Asthose skilled in the art will recognize, other formats are available,including a transmission control program, internet protocol (TCP/IP)packet format, a user datagram protocol, internet protocol (UDP/IP)packet format, an asynchronous transfer mode (ATM) cell packet format, aserial line interface protocol (SLIP) protocol format, a point-to-point(PPP) protocol format, a point-to-point tunneling protocol (PPTP)format, a NETBIOS extended user interface (NETBEUI) protocol format, anAppletalk protocol format, a DECnet, BANYAN/VINES, an internet packetexchange (IPX) protocol format, and an internet control message protocol(ICMP) protocol format.

[0091] Note that FIG. 1 and other figures described herein include lineswhich may refer to communications lines or which may refer to logicalconnections between network nodes, or systems, which are physicallyimplemented by telecommunications carrier devices. These carrier devicesinclude circuits and network nodes between the circuits including, forexample, digital access and cross-connect system (DACS), regenerators,tandems, copper wires, and fiber optic cable. It would be apparent topersons of ordinary skill that alternative communications lines can beused to connect one or more telecommunications systems devices. Also, atelecommunications carrier as defined here, can include, for example, aLEC, a CLEC, an IXC, an Enhanced Service Provider (ESP), a global orinternational services provider such as a global point-of-presence(GPOP), and an intelligent peripheral.

[0092] EO 104 and AT 106 are connected by trunk 116. A trunk connects anAT to an EO. Trunk 116 can be called an inter machine trunk (IMT).

[0093] AT 106 and EO 108 are connected by a trunk 118 which can be anIMT. EO 108 and ISP 112 can be connected by a private line 120 with adial tone. Private line 120 with a dial tone can be connected to a modembay or access converter equipment at ISP 112. Private line 120 can alsoconnect a PBX (not shown) to EO 108, for example. Examples of a privateline are a channelized T1 or PRI. ISP 112 can also attach to theInternet by means of a pipe or dedicated communications facility. A pipecan be a dedicated communications facility. Private line 120 can handledata modem traffic to and from ISP 112.

[0094] Trunks 116 and 118 can handle switched voice traffic and datatraffic. For example, trunks 116-118 can include digital signals DS1-DS4transmitted over T1-T4 carriers. Table 2 provides typical carriers,along with their respective digital signals, number of channels, andbandwidth capacities. TABLE 2 Bandwidth in Number of Designation ofMegabits per Digital signal channels carrier second (Mbps) DS0 1 None0.064 DS1 24 T1 1.544 DS2 96 T2 6.312 DS3 672 T3 44.736 DS4 4032 T4274.176

[0095] Alternatively, trunks 116 and 118 can include optical carriers(OCs), such as OC-1, OC-3, etc. Table 3 provides typical opticalcarriers, along with their respective synchronous transport signals(STSs), ITU designations, and bandwidth capacities. TABLE 3International Electrical signal, Telecommuni- or synchronous cationsUnion Bandwidth in Optical carrier transport signal (ITU) Megabits per(OC) signal (STS) terminology second (Mbps) OC-1 STS-1 51.84 OC-3 STS-3STM-1 155.52 OC-9 STS-9 STM-3 466.56 OC-12 STS-12 STM-4 622.08 OC-18STS-18 STM-6 933.12 OC-24 STS-24 STM-8 1244.16 OC-36 STS-36 STM-121866.24 OC-48 STS-48 STM-16 2488.32

[0096] As noted, private line 120 is a connection that can carry datamodem traffic. A private line is a direct channel specifically dedicatedto a customer's use between two specificed points. A private line canalso be known as a leased line. In one embodiment, private line 120 isan ISDN/primary rate interface (ISDN PRI) connection. An ISDN PRIconnection includes a single signal channel (called a data or D channel)on a T1, with the remaining 23 channels being used as bearer or Bchannels. (Bearer channels are digital channels that bear voice and datainformation.) If multiple ISDN PRI lines are used, the signaling for allof the lines can be carried over a single D channel, freeing up theremaining lines to carry only bearer channels.

[0097] Network 100 also includes a CCIS network for call setup and calltear down. Specifically, FIG. 1 includes a Signaling System 7 (SS7)network 114. This SS7 network is described more fully below withreference to FIG. 3 below.

[0098]FIG. 2 is a block diagram illustrating an overview of a standardtelecommunications network 200, providing both LEC and IXC carrierservices between subscribers located in different LATAs.Telecommunications network 200 is similar to telecommunications network100, except that calling party 102 and a called party 224 are located indifferent LATAs. In other words, calling party 102 is homed to ingressEO 104 in a first LATA, whereas called party 224 is homed to an egressEO 222 in a second LATA. Calls between subscribers in different LATAsare long distance calls that are typically routed to IXCs. Sample IXCsin the United States include AT&T, MCI and Sprint.

[0099] AT 106 provides connection to points of presence (POPs) 202, 204and 206. IXCs 214, 216 and 218 provide connection between POPs 202, 204and 206 (in the first LATA) and POPs 208, 210 and 212 (in the secondLATA). POPs 208, 210 and 212, in turn, are connected to AT 220, whichprovides connection to egress EO 222. Called party 224 receives callsfrom EO 222, which is its homed EO. Alternatively, it would be apparentto a person having ordinary skill in the art that an AT 106 can also be,for example, a CLEC, or other enhanced service provider (ESP), aninternational gateway or global point-of-presence (GPOP), or anintelligent peripheral.

[0100] In addition to providing a voice connection from calling party102 to called party 224, the PSTN provides calling party 102 a dataconnection to an ISP 226. ISP 226 is similar to ISP 112.

[0101] B. The Signaling Network{TC\l2″}

[0102]FIG. 3 illustrates SS7 network 114 in greater detail. SS7 network114 is a separate network used to handle the set up, tear down, andsupervision of calls between calling party 102 called party 110 (or ISP226). SS7 network 114 includes service switching points (SSPs) 316, 318,320 and 322, signal transfer points (STPs) 302, 304, 306, 308, 310 and312, and service control point (SCP) 314.

[0103] In the SS7 network, the SSPs are the portions of the backboneswitches providing SS7 functions. The SSPs can be, for example, acombination of a voice switch and an SS7 switch, or a computer connectedto a voice switch. The SSPs communicate with the switches usingprimitives, and create packets for transmission over the SS7 network.

[0104] EOs 104, 222 and ATs 106, 220 can be respectively represented inSS7 network 114 as SSPs 316, 318, 320 and 322. Accordingly, theconnections between EOs 104, 222 and ATs 106, 220 (presented as dashedlines) can be represented by connections 334, 336, 338, and 340. Thetypes of these links are described below.

[0105] The STPs act as routers in the SS7 network, typically beingprovided as adjuncts to in-place switches. The STPs route messages fromoriginating SSPs to destination SSPs. Architecturally, STPs can and aretypically provided in “mated pairs” to provide redundancy in the eventof congestion or failure and to share resources (i.e., load sharing isdone automatically). As illustrated in FIG. 3, STPs can be arranged inhierarchical levels, to provide hierarchical routing of signalingmessages. For example, mated STPs 302, 304 and mated STPs 306, 308 areat a first hierarchical level, while mated STPs 310, 312 are at a secondhierarchical level.

[0106] SCPs provide database functions. SCPs can be used to provideadvanced features in an SS7 network, including routing of specialservice numbers (e.g., 800 and 900 numbers), storing informationregarding subscriber services, providing calling card validation andfraud protection, and offering advanced intelligent network (AIN)services. SCP 314 is connected to mated STPs 310 and 312.

[0107] In the SS7 network, there are unique links between the differentnetwork elements. Table 4 provides definitions for common SS7 links.

[0108] Referring to FIG. 3, mated STP pairs are connected by C links.For example, STPs 302, 304, mated STPs 306, 308, and mated STPs 310, 312are connected by C links (not labeled). SSPs 316, 318 and SSPs 320, 322are connected by F links 342 and 344.

[0109] Mated STPs 302, 304 and mated STPs 306, 308, which are at thesame hierarchical level, are connected by B links 350, 352, 366 and 372.Mated STPs 302, 304 and mated STPs 310, 312, which are at differenthierarchical levels, are connected by D links 346, 348, 354 and 356.Similarly, mated STPs 306, 308 and mated STPs 310, 312, which are atdifferent hierarchical levels, are connected by D links 358, 360, 368and 370.

[0110] SSPs 316, 318 and mated STPs 302, 304 are connected by A links334 and 336. SSPs 320, 322 and mated STPs 306, 308 are connected by Alinks 338 and 340.

[0111] SSPs 316, 318 can also be connected to mated STPs 310, 312 by Elinks (not shown). Finally, mated STPs 310, 312 are connected to SCP 314by A links 330 and 332.

[0112] For a more elaborate description of SS7 network topology, thereader is referred to Russell, Travis, Signaling System #7, McGraw-Hill,New York, N.Y. 10020, ISBN 0-07-054991-5, which is incorporated hereinby reference in its entirety. TABLE 4 SS7 link terminology DefinitionsAccess (A) links A links connect SSPs to STPs, or SCPs to STPs,providing network access and database access through the STPs. Bridge(B) links B links connect mated STPs to other mated STPs. Cross (C)links C links connect the STPs in a mated pair to one another. Duringnormal conditions, only network management messages are sent over Clinks. Diagonal (D) links D links connect the mated STPs at a primaryhierarchical level to mated STPs at a secondary hierarchical level.Extended (E) links E links connect SSPs to remote mated STPs, and areused in the event that the A links to home mated STPs are congested.Fully associated (F) F links provide direct connections between linkslocal SSPs (bypassing STPs) in the event there is much traffic betweenSSPs, or if a direct connection to an STP is not available. F links areused only for call setup and call teardown.

IV. The Present Invention{TC\l1″}

[0113] A. Overview of Data Bypass{TC\l2″}

[0114]FIG. 4 includes an overview of an enhanced telecommunicationsnetwork 400 according to the present invention. This invention relatesto the convergence of two types of networks, i.e., voice and datanetworks. Telecommunications network 400 provides a bypass connectionfrom the ingress EO 104 (a class 5 switch) or from AT 106 (a class ¾switch) to the called party 110 and ISP 112. Alternatively, it would beapparent to a person having ordinary skill in the art that an AT 106 canalso be, for example, a CLEC, or other enhanced service provider (ESP),an international gateway or global point-of-presence (GPOP), or anintelligent peripheral. The connection is called a bypass connectionbecause it bypasses the connections from the egress EO 108 to calledparty 110 and ISP 112. In other words, for example, the facilities ofthe incumbent LEC (ILEC) terminating the call of originating caller 102are bypassed.

[0115] Telecommunications network 400 includes open architectureplatform 402. Telecommunications network 400 also includes trunks 404and 406, connection 408, and trunk 410, which, for example, respectivelyconnect open architecture platform 402 to EO 104, to AT 106 (i.e., anytelecommunications carrier), to ISP 112 (i.e., or a business entity'sprivate data network), and to called party 110. In a preferredembodiment, trunks 404 and 406 can handle both data and voice traffic.However, trunks 404 and 406 must be capable of handling at least datatraffic. In a preferred embodiment, connection 408 and trunk 410 canhandle data or voice traffic. However, connection 408 must be capable ofhandling at least data traffic (i.e. including any type of digitizeddata). It should also be apparent to a person having ordinary skill,that connection 408, for example, is a logical connection that cancontain various network devices.

[0116] As noted, open architecture platform 402 can receive both voiceand data traffic. This traffic can be received from any network node ofa telecommunications carrier. A telecommunications carrier can include,for example, a LEC, a CLEC, an IXC, and an Enhanced Service Provider(ESP). In a preferred embodiment, this traffic is received from anetwork node which is, for example, a class 5 switch, such as EO 104, orfrom a class ¾ switch, such as AT 106. Alternatively, the network systemcan also be, for example, a CLEC, or other enhanced service provider(ESP), an international gateway or global point-of-presence (GPOP), oran intelligent peripheral. Accordingly, open architecture platform 402integrates both voice and data traffic on a single platform.

[0117] Data traffic refers, for example, to a data connection between acalling party 102 (using a modem) and a server 412 in ISP 112. A dataconnection is established between calling party 102 and EO 104, thenover a trunk 404 to open architecture platform 402, then over aconnection 408 to ISP 112, and then over a connection 414 to server 412.Alternatively, the connection can be established from calling party 102to EO 104, then to AT 106, then over trunk 406 to open architectureplatform 402, then over connection 408 to ISP 112, and then overconnection 414 to server 412.

[0118] Voice traffic refers, for example, to a switched voice connectionbetween calling party 102 and called party 110. It is important to notethat this is on a point-to-point dedicated path, i.e., that bandwidth isallocated whether it is used or not. A switched voice connection isestablished between calling party 102 and EO 104, then over trunk 404 toopen architecture platform 402, then over trunk 410 to called party 110.Alternatively, the connection can be established from calling party 102to EO 104 and then to AT 106, then over trunk 406 to open architectureplatform 402, then over trunk 410 to called party 110. In anotherembodiment, AT 106 can also be, for example, a CLEC, or other enhancedservice provider (ESP), an international gateway or globalpoint-of-presence (GPOP), or an intelligent peripheral.

[0119] Open architecture platform 402, and communications links 404,406, 408 and 410 comprise the resources of an ILEC or a competitive LEC(CLEC). A CLEC may or may not provide inter-LATA calls, which aretraditionally handled by IXCs.

[0120] B. Detailed Description of Data Bypass{TC\l2″}

[0121] 1. The Open Architecture Platform {TC\l3″}

[0122]FIG. 5 illustrates open architecture platform 402 in detail. Openarchitecture platform 402 includes an open architecture switch 502 and avoice switch 506. Open architecture platform 402 receives data and voicetraffic from the PSTN (over communications links 404 and 406) andseparates data traffic from voice traffic. Data traffic is handled byopen architecture switch 502, while voice traffic is handled by voiceswitch 506.

[0123] Voice calls switched by voice switch 506 are sent out from theopen architecture platform 402. For example, an outbound voice call issent from voice switch 506 over communications link 410 to called party110.

[0124] On the other hand, outbound data calls are passed onto a modemNAS bay (which can be a resource on open architecture switch 502) formodem termination. For example, a data signal (e.g., in the PPPprotocol) can be converted to protocol used by data networks (e.g., intointernet protocol (IP) data packets), for transmission over routers to adata network, such as an ISP. Specifically, an outbound data call willbe sent to modem NAS bay 514, then to routers (not shown), and then sentto ISP 112 over communications link 408. As another example, a virtualprivate networking protocol can be used to create a “tunnel” between theremote user and a data network. For example, calling party 102, using aserver that supports a tunnel protocol (e.g., PPTP) will have anextended virtual private network connection with a data network, such asISP 112.

[0125] As noted, open architecture platform 402 comprises openarchitecture switch 502 and voice switch 506. Open architecture switch502 includes gateway (GW) 508, tandem network access server (NAS) bay504, and modem NAS bay 514.

[0126] GW 508 comprises SS7 gateway (SS7 GW) 512, control server 510,and database 516 communicating with control server 510. GW 508 caninclude multiple SS7 GWs 512 and multiple control servers 510 (eachhaving one or more databases 516). Database 516 can be internal to GW508 or alternatively, external to GW 508.

[0127] It is important to note that the open architecture platform isdefined by the function of the resources comprising it, and how theseresources are interrelated. Accordingly, there is no reason that GW 508,tandem NAS bay 504, and modem NAS bay 514 would be required to becollocated, or limited to a particular geographical area, see FIG. 9B,below. Further, the architecture is infinitely scalable over geographicboundaries. As long as any resources match the functions andinteroperabilities defined herein, then such resources comprise openarchitecture platform 402. The same holds true for the subcomponentscomprising any platform resources, e.g., the subcomponents of GW 508(defined below).

[0128] Gateway 508 has two functions: interfacing with the CCISsignaling network (e.g., the SS7 signaling network 114) and interfacingwith a plurality of control servers to control a plurality of NAS bays.SS7 GW 512 provides the first function of providing an interface to theSS7 signaling network 114. The SS7 signaling information is conveyed tocontrol server 510.

[0129] Control server 510 provides the second function of controllingone or more NAS bays which comprise resources of open architectureswitch 502. Specifically, control server 510 communicates with tandemNAS bay 504 and modem NAS bay 514. This communication is performed via aprotocol understood by the open architecture platform 402 resources,referred to herein as an open architecture protocol.

[0130] The open architecture protocol is represented by dotted lines 518and 520. In one embodiment, the open architecture protocol is thenetwork access server (NAS) messaging interface (NMI) protocol, createdby XCom Technologies Inc. This protocol is defined by a series ofcontrol messages, which are defined below in table form. Anotherprotocol is called the Internet Protocol Device Control (IPDC), recentlyreleased by a Technical Advisory Council (TAC) and Level 3Communications, Inc. The IPDC specification, which is incorporatedherein by reference in its entirety, is available in its current drafton the Level 3 Communications web site http://www.Level3.com. It will beapparent to those skilled in the art that any comparable protocol willsuffice, so long as the protocol permits the resources of the openarchitecture platform 402 to communicate with one another.

[0131] In one embodiment, as depicted in FIG. 9B, below, one or more ofSS7 GW 512, control server 510, database 516, and NAS are geographicallydiverse devices (or applications running on devices). For example, thesedevices can be connected by communications links using Ethernet, framerelay, asynchronous transfer mode (ATM), or any other conceivableprotocols. In another embodiment, one or more of SS7 GW 512, controlserver 510, database 516, and NAS 902 are collocated devices (orapplications running on devices), see FIG. 9B.

[0132] In a preferred embodiment, SS7 GW 512 and control server 510 areapplications running on one or more collocated host computers.Alternatively, the applications can be run on one or more geographicallydiverse computers. For example, the host computers can be one or moreredundantly interconnected SUN workstations, model 450, for example,available from Sun Microsystems. FIGS. 6 and 7 below are representationsused to illustrate the intercommunications between SS7 GW 512 andcontrol server 510 in the preferred embodiment.

[0133]FIG. 6 symbolically illustrates an example SS7 GW 512 application(as implemented using computer programs). The SS7 GW 512 application,labeled open architecture platform (OAP) SS7 GW application 600,provides communications between SS7 network 114 and open architectureswitch 502. The SS7 signaling information is translated into, forexample, an object-oriented, or wire line protocol format form forcross-platform compatibility, ease of transport, and parsing.

[0134] As illustrated in FIG. 6, OAP SS7 adapter 602 communicatesdirectly with the lower level libraries, such as TCP/UDP 604 and IP 606,provided by manufacturers of SS7 interface cards and by manufacturers ofhost computers used in particular applications. OAP SS7 comservice 608of OAP comservice 610 queues messages between OAP SS7 adapter 602 andthe remainder of OAP SS7 GW application 600. It is important to notethat any number of protocols recognized by those skilled in the art canbe used. For example, instead of TCP/IP or UDP/IP, the X.25 protocol canbe used instead.

[0135] OAP task master 620 maintains a pool of threads that are assignedto one or more OAP task slaves 622. OAP SS7 GW application 600 is cuedby an OAP metronome 624 to read tasks from OAP scheduler 626. OAP taskslave 622 is an abstract base class from which is derived a number ofunique slaves that may initiate SS7 signals in response to messagingfrom SS7 network 114.

[0136] Messages from SS7 network 114 are received through SS7 adapter602 and passed to OAP comservice 610 and OAP task master 620. OAP taskmaster 620 schedules tasks to respond to each of the messages. Eachmessage is then passed to OAP comservice 610 again to be transferred toan appropriate control server 510.

[0137] Messages may also be stored in OAP historian 628. If appropriate,the tasks from OAP scheduler 626 are performed and appropriate messagesare passed back to SS7 network 114 through OAP adapter 602.

[0138] The processing of messages from control servers 510 operates in asimilar manner. The messages come through OAP comservice 610 and arepassed to OAP task master 620. OAP task master 620 then determinesappropriate tasks, if any, and transfers the messages on to the adapterto be sent on SS7 network 114.

[0139] An example control server 510 application (as implemented usingcomputer programs) is illustrated symbolically in FIG. 7. FIG. 7illustrates the OAP control server application 700, which is a callprocessing coordinator.

[0140] OAP control server application 700 receives SS7 signals in objector wire line protocol form from SS7 GW 512. Based upon the signals, ithandles resource allocation, signaling responses and translationservices.

[0141] OAP comservice 708 is similar to OAP comservice 610 (in SS7 GW512) because it operates to receive and send messages between itself andSS7 GW application 600. OAP task master 710 determines and schedulestasks to be performed by OAP control server application 700. OAP taskslave 712 is an abstract base class from which are derived uniqueclasses for each message.

[0142] OAP translator 714 object or wire line protocol format mapstelephone numbers onto OAP database 716. OAP database 716 contains thedestination of the call, any class functions associated with the call,the type of routing algorithm that should be used, and a statusassociated with the telephone number. OAP router service 718 is anobject or wire line protocol which transports requests for routingpaths, including both delivery and receipt of responses.

[0143] OAP state 720 is a collection of data on the state of eachcircuit identifier code (CIC) which exists between a given SS7 GW 512originating point code (OPC) and a destination point code (DPC). Thisdata includes the current status of the trunk and information on recentmessaging. The roles of the CIC, the OPC and the DPC with respect to SS7network 114 are discussed in greater detail below.

[0144] OAP NAS comservice 706 is a communications object or wire lineprotocol format that is responsible for receipt and delivery of messagesfrom NAS bays 504 and 514. When a message is received from SS7 GW 512,it is handed to OAP task master 710. OAP task master 710 instantiatesOAP task slave 712 object or wire line protocol format suitable for theparticular type of message. If a call transaction is initiated, OAP taskslave 712 requests information concerning the called subscriber from OAPtranslator 714, and a route to reach the subscriber from OAP routerservice 718. OAP state 720 is updated to indicate that a call is inprogress from the CIC associated with the message. Finally, NAScomservice 706 signals NAS bays 504, 514 to instantiate the route forthe call.

[0145] When a NAS bay responds with a control message, OAP NAScomservice 706 converts the message into an object or wire line protocolformat and passes the object or wire line protocol format to OAP taskmaster 710. OAP task master 710 instantiates a suitable OAP task slave712. By checking OAP state 720, task slave 720 correlates the messagewith an earlier received message from OAP SS7 GW application 600, andformulates a response message to be delivered to OAP SS7 GW application600 through OAP comservice 708.

[0146] Maintenance and Monitoring interface (MMI) 722 is a graphicaluser interface that communicates with either SS7 gateway application 600or control server application 700 to update the starting configurationor the running state, and to monitor and modify various runtime factors.Such factors may include in-progress calls, circuit supervisoryinformation, circuit deployment and maintenance, and similar activities.OAP router service 718 runs as a query daemon, providing a variety ofrouting strategies for the distribution of incoming and outgoing callsacross the large, redundant network, OAP control server application 700includes OAP Historian 724.

[0147]FIG. 8 illustrates an exemplary NAS bay 802. NAS bay 802 is ageneric view of either tandem NAS bay 504 or modem NAS bay 514. NAS bay802 includes modules 804, 806, 808, and 810. Each of these modules is aslot card used to implement one or more interfaces with network lines. Aline is a set of channels (e.g., a line on a T1 carrier). A channel is atime-slot on a line. Accordingly, each connection established with a NASbay 802 can be uniquely identified by a module/line/channel identifier.Table 5 provides definitions for NAS bay terms. TABLE 5 NAS bayterminology Definitions network access A NAS bay is a facility thathouses server (NAS) bay modules. Lines (having channels) are connectedto the modules. Each connection into the bay can be uniquely identifiedby a module/line/channel identifier. module Modules are slot cards thatreceive communication lines, and perform functions on the channels ofthe lines. Modules can be used to perform time modulation anddemodulation, to name a few functions. line A line is a set of channels(e.g., a line on a T1 carrier) interconnected with modules. channel Achannel is a time-slot on a line.

[0148] Referring back to FIG. 5, tandem NAS bay 504 receives data andvoice traffic from the PSTN (i.e., from the EO 104 over connection 404or from AT 106 over connection 406). Call traffic can also originatefrom, for example, a CLEC, or other enhanced service provider (ESP), aninternational gateway or global point-of-presence (GPOP), or anintelligent peripheral. Tandem NAS bay 504 also cross-connects anincoming data call to modem NAS bay 514 through a matrix using timedivision multiplexing (TDM). This function, of providing pass-through ofdata, is referred to herein as data bypass.

[0149] Modem NAS bay 514 terminates a data call to one of its modems andthe modems allow for the device to convert the inbound data call fromone protocol to another. In lieu of modem NAS bay 514, anyart-recognized devices providing the functions of modulation anddemodulation can be used. Examples include a software implementation (anapplication running on a computer), a modem using a digital signalprocessor (DSP), or a data service unit/channel service unit (DSU/CSU).In one embodiment, modem NAS bay 514 can provide themodulation/demodulation function, of converting the signal from a firstdata format used by the telecommunications services provider thatprovides access to the open architecture platform 402 (e.g., in PPPformat) to a second format (e.g., IP data packets) used by a destinationdata network such as ISP 112. As those skilled in the art willrecognize, the particular second format need not be limited to IP datapackets, depending primarily on the destination data network. As thoseskilled in the art will recognize, other protocol formats include atransmission control program, internet protocol (TCP/IP) packet format,a user datagram protocol, internet protocol (UDP/IP) packet format,routing table protocol (RTP) (e.g., Banyan VINES) format, anasynchronous transfer mode (ATM) cell packet format, a serial lineinterface protocol (SLIP) protocol format, a point-to-point (PPP)protocol format, a point to point tunneling protocol (PPTP) format, aNETBIOS extended user interface (NETBEUI) protocol format, an Appletalkprotocol format, a DECNet format, and an internet packet exchange (IPX)protocol format.

[0150] In the alternative, a virtual private networking protocol can beused to create a “tunnel” between a remote user (e.g., calling party 102using a server that supports tunneling) and the destination data network(e.g., ISP 112). One example of a virtual private networking protocol isPPTP.

[0151] An exemplary modem NAS bay 514 is an ASCEND access concentrator,model TNT, available from Ascend Communications, Inc., which isanalogous to a NAS bay 802 with modems functioning on modules 804, 806,808, and 810. Those skilled in the art will recognize that the modemfunction described above is conventionally performed by the destinationdata networks (e.g., ISP 112), not by an ILEC or a CLEC. In this sense,the present invention simplifies the functions of the destination datanetwork providers, such as ISPs.

[0152] It must be noted that it is not necessary to implement thepresent invention by way of conventional NAS devices. Any networkelements providing the dual functions of data bypass (i.e., as providedby tandem NAS bay 504) and conversion of data by means of modemtermination into a format usable by a data network (i.e., as provided bymodem NAS bay 514) will suffice. Those skilled in the art will recognizethat a number of network devices can be combined to provide thesefunctions.

[0153] As those skilled in the art will recognize, transmission controlprotocol (TCP) and internet protocol (IP) (collectively called TCP/IP)form a packet switching protocol comprised of the TCP and IP protocols,which are layers of protocols that act together. IP is a protocol thatfunctions at the network layer of the Open Systems Interconnect (OSI)data network architecture model, and as noted, provides packetizing ofdata into units also called datagrams, containing address information.TCP is a protocol that functions at the session and transport layers ofthe OSI data model, providing the separation, transmission,retransmitting, and sequencing of data packets. TCP establishes aconnection between two systems intending to exchange data, performingmessaging control functions. IP is said to “ride on top of” TCP, i.e.,IP is a simpler protocol than TCP in that IP only addresses and sends.TCP breaks a message down into IP packets and uses CHECKSUM errorchecking logic to guaranty delivery of the message from the first systemto the second.

[0154] It is important to note that this invention deals with theconvergence of voice and data networks. The reader should appreciatethat voice networks and data networks were formerly two separatenetworks. The office classification switching hierarchy discussed aboveis a voice network architecture and has no correlation to the OSI modelwhich is a data networking architecture.

[0155] It is also important to note that open architecture switch 502can include one or more of gateways 508, one or more tandem networkaccess server (NAS) bays 504 and one or more modem NAS bays 514.Therefore, the number of these elements is not important, so long astheir respective functions are met.

[0156]FIG. 9A is a more elaborate view of one embodiment of the openarchitecture platform of the invention. The open architecture platformshown in FIG. 9A is the same as open architecture platform 402 (shown inFIG. 5), except for the additional resources described below.

[0157] In FIG. 9A, NAS bay 902 provides both the tandem functions oftandem NAS bay 504 and the modem functions of modem NAS bay 514. Inother words, NAS bay 902 will provide the data bypass function of tandemNAS bay 504, as well as the modem termination function of modem NAS bay514. Voice traffic is transmitted over trunks 930 or 932 to voice switch506. Voice switch 506 can transmit the voice traffic, for example, overprivate line 934 to PBX 912.

[0158] If the call comprises data traffic, NAS bay 902 will use modemsto convert the incoming data call into a form suitable for a destinationdata network (e.g., PPP data packets) for transmission to other datanodes over open architecture platform 402. For example, the resultingdata packets are transmitted over an Ethernet/WAN connection 903 (usingan Ethernet/WAN protocol), in conjunction with TCP/IP. It would beapparent to one of skill in the art that alternative networkarchitecture could be used, such as, for example, FDDI, SONET, ATM, etc.

[0159] Connection 903 terminates in internal backbone 936. Internalbackbone 936 can be any type of data link. Routers 904, 906 route the IPdata packets from internal backbone 936 to ISPs 938, 940. Exemplarynetwork routers include network routers from various companies such as,CISCO, 3COM, NETOPIA, and NORTEL, or a host computer running routingsoftware. Specifically, the data packets are transmitted from router 904to router 908 in ISP 938, and from router 906 to router 910 in ISP 940.Thus, the customers of ISPs 938, 940 can dial into communication serversat the ISP location, which have dedicated routers 908, 910. Thus, ISPs938, 940 can route data traffic to routers on open architecture platform402.

[0160] In one embodiment, ISP 948 can use a network service provider(NSP) to provide a modem pool for use by the customers of ISP 948. ACLEC implementing open architecture platform 402 can comprise an NSP.Modems in NAS bay 902 can be used by subscribers of ISPs 938, 940 and948 for interconnectivity, and traffic can also be routed to othernetwork nodes via the routers. Modem pooling at the NSP level reducescapital expenditures by ISPs 938, 940, 948.

[0161] The invention enables network access point (NAP) switching whichinvolves exchanging data traffic on the architecture. A NAP switches thecall based on routing instructions it receives. Online services can beperformed so-called “on the box.”

[0162] NAS bay 942 can be the same type of device as NAS bay 902, inthat it provides both the tandem functions of tandem NAS bay 504, andthe modem functions of modem NAS bay 514. NAS bay 942 is used torepresent other connections that can be established with openarchitecture platform 402.

[0163] Calling party 914 is another party that can establish a dataconnection using a modem connected to a host computer. However, callingparty 914, via its host computer, has the additional feature ofproviding voice over IP (VOIP) service over communications link 944.

[0164] PBX 916 is a centralized switch providing its collocatedcustomers both switching and access to NAS bay 942. This access isprovided over T1/ISDN PRI private line 946.

[0165] It is possible to access open architecture platform 402 using anytype of digital subscriber line (DSL) connection. Calling party 924 andcomputer 922 access NAS bay 942 over a high bit rate DSL (HDSL), knownas a single pair HDSL (SDSL) 920. HDSL can place a two-way T1 on anormal unshielded, bridged (but not loaded) twisted pair copper wireloop 982. In an embodiment of SDSL, an existing single pair copper wireon the local loop is used to transmit full duplex data at up to 768Kbps. Transmission at 1.54 Mbps is achieved by using two SDSL lines,i.e., two pairs of wires.

[0166] SDSL 920 permits simultaneous voice and data transmission througha DSL device 918 (e.g., a splitter), which can be collocated withcalling party 924 and computer 922. Alternatively, access can beobtained without a splitter device. In addition, calling party 924 andcomputer 922 can access NAS bay 942 over ISDN DSL (IDSL) link 926. In anembodiment of IDSL, an existing local loop, i.e., a single pair ofcopper wires, is used to transmit full duplex data at 128 Kbps.Alternatively, calling party 924 and computer 922 can access NAS bay 942over xDSL 928. In an embodiment of xDSL, an existing local loop, i.e., asingle pair of copper wires, is used to transmit digital subscriber linecommunications.

[0167] In one embodiment of the invention, a CLEC implementing openarchitecture platform 402 can accept data traffic from other CLECs orILECs, providing data bypass for the egress leg of data calls. In suchan embodiment, the implementing CLEC can charge back the other CLECs orILECs an “unbundled element” for providing this service to the egressfacilities involved (i.e., the egress EOs belonging to the ILECs or usedby the other CLECs'). It is important to note that reciprocalcompensation does not exist everywhere and other arrangements do exist.While this is the predominant arrangement, this is not necessarily theonly arrangement. This approach, of having an NSP/CLEC charge back anILEC or other CLEC for offloading of data traffic, can save theoffloaded CLEC or ILEC significant capital expenditures related to theswitching of data traffic.

[0168] Voice traffic is transmitted over trunks 930 or 932 to voiceswitch 506. Voice switch 506 can transmit the voice traffic, forexample, over private line 934 to PBX 912.

2. Data Bypass Operations{TC\l3″}

[0169] FIGS. 10A-10B depict flow charts illustrating how an originatingcaller gains access to open architecture platform 402. FIGS. 10A-10B aredescribed with reference to FIGS. 1, 4, 5 and 9.

[0170]FIG. 10A depicts a method 1000 for receiving an inbound call whichbypasses the facilities of an egress switch according to the presentinvention. Alternatively, other call flows are possible, including acall requiring a modem calling back for security reasons, using outboundcalling from open architecture platform 402.

[0171] In step 1002 of FIG. 10A, the technique receives signalinginformation to set up data calls and voice calls from a calling party toa called party. In step 1004, the technique converts the signalinginformation into an open architecture protocol format. In step 1006,data calls and voice calls are received at open architecture switch 502.In step 1008, the technique distinguishes between data calls and voicecalls. In step 1010, the technique controls NASs, i.e., NAS bays 504 and514, using the open architecture protocol. In step 1012, the methodterminates data calls to modems in a modem NAS bay, e.g., in modem NAS514, for conversion to a packetized data format for transmission tonetwork nodes. Alternatively, in step 1012, a tunnel is establishedbetween the user and the destination data network. In step 1014, themethod transmits voice calls to a voice switch for transmission to thecalled party.

[0172]FIGS. 10B and 10C depict more detailed description of thetechnique outlined in FIG. 10A. Specifically, these figures depict aninbound call flow into open architecture platform 402. An inbound callis where an incoming call (into the open architecture platform) isconnected to a called party (for a voice connection) or an ISP (for adata connection).

[0173] Referring to FIG. 10B, in step 1018 an originating caller 102(shown in FIG. 1) gains access to LEC facilities. This is performedaccording to known methods as described with respect to FIG. 1. As oneexample, originating caller 102, using a telephone, can go off-hook toplace a switched voice call to the LEC facilities. As another example,calling party 102 can use a host computer, in concert with a modem, toestablish a data connection with the LEC facilities (i.e., the modem ofcalling party 102 takes the line off-hook). As those skilled in the artwill recognize, any of the access methods described with respect to FIG.9A, in addition to other known methods, can be used to access the LECfacilities.

[0174] In step 1020, signaling information for the call is received bythe homed EO, the originating EO, indicating that calling party 102 isattempting to make a call. As noted, the homed EO, often referred to asa central office CO, is the EO having a direct connection with theoriginating caller. (This is true for voice calls and for data calls.)In FIG. 1, the homed EO is ingress EO 104. Conventionally, for this legof the call, i.e., between the telephone or modem of calling party 102and EO 104, the LEC uses in-band signaling implemented with pulse ortone dialing. The homed EO then sends back a dial tone to calling party102.

[0175] In step 1022, the originating caller, calling party 102, hears adial tone and dials a telephone number to access the open architectureplatform 402. The dialed number, for example, in the currently useddomestic US 10-digit standard NPA-NXX-XXXX format (i.e., Europe, forexample, has a different 32 digit standard), can be the telephone numberof called party 110, or a number used to access an ISP which can bevirtually mapped to a table of terminating points.

[0176] In step 1024, the LEC facilities perform a table lookup and thentransmit the call to a facility (e.g., a class 4 AT switch or a class 5EO switch) that is connected to open architecture platform 402. First,EO 104 will look up the dialed number in translation tables (external tothe EO) which will indicate which switch of the LEC facility is toreceive the call. Next, EO 104 will transmit appropriate signalinginformation to transmit the call along a path to that facility.

[0177] It should be noted that if the regulatory environment were tochange as to permit CLECs or other interconnecting parties to accessoriginating office triggers from ILECs, then it would be possible toroute the call traffic differently.

[0178] It should be noted that this step is optional, because it ispossible that EO 104 (the homed EO) provides a direct connection withopen architecture platform 402. It is also possible that calling party102 will have a connection to a network node or system (e.g. anintelligent peripheral, a GPOP, etc.) that is not an EO or AT switch,which will provide a direct connection to open architecture platform402. It is also possible that the homed EO will provide a connection toanother type of network device (i.e., not an EO or an AT) that will, inturn, provide a direct connection to open architecture platform 402.

[0179] The leg of the call described in step 1024 can be connected usingin-band signaling or out-of-band signaling. (The same is true for thelegs of the call following this leg.) In one embodiment, SS7 signalingis used to terminate the call to the facility providing access to theopen architecture platform 402. Referring to FIG. 4 or FIG. 9A, AT 106and EO 104 are, for example, facilities providing access to openarchitecture platform 402. Alternatively, these facilities couldinclude, for example, a CLEC, or other enhanced service provider (ESP),an international gateway or global point-of-presence (GPOP), or anintelligent peripheral.

[0180] With SS7 signaling, the ISDN User Part (ISUP) protocol can beused. ISUP features numerous messages that are transmitted within theSS7 network, which are used to establish call set up and call teardown.In the present case, an initial address message (IAM) is sent to AT 106or EO 104. Of course, AT 106 can also be, for example, a CLEC, or otherenhanced service provider (ESP), an international gateway or globalpoint-of-presence (GPOP), or an intelligent peripheral. The IAM caninclude such information as the calling party number (i.e., thetelephone number of calling party 102, although the IAM doesn'tnecessarily contain calling party, especially in local environment), thecalled party number (i.e., the telephone number dialed by calling party102), the origination point code (OPC), the destination point code(DPC), and the circuit identification code (CIC). (The OPC, DPC and CICwere discussed above with respect to FIG. 7). The OPC identifies theswitch from which the call is to be transmitted on the present leg ofthe call, which in this case is homed EO 104. The DPC identifies theswitch to which the present leg of the call is to be routed. Taking theexample of a call that is connected to open architecture platform 402 byAT 106, the SS7 signaling will transmit the call from EO 104 to AT 106.The CIC identifies the bearer channel over which the call is coming into AT 106 from EO 104. Each AT 106 looks at the called number and thendoes its own routing, by reviewing the contents of the IAM anddetermining the next switch to send the call to, by setting the next DPCin order to continue routing the call.

[0181] It should be noted that ISUP messages are transmitted fromsignaling point to signaling point in the SS7 network in the above-notedmanner, until the signaling is completed to a destination switch, nodeor trunk (i.e., at a called party). For example, it is possible thatonce the call is sent to homed EO 104, it is sent to intermediateswitches (i.e., other EOs and ATs) before it arrives at AT 106. In thiscase, each switch along the path of the call will create an IAM withinformation reflecting the next leg of the call. For each leg, the OPCand DPC are modified, and the receiving switch looks for the call in thebearer channel specified by the CIC which is included in the IAM.

[0182] In step 1026, the LEC facilities perform a table lookup and thentransmit the call to open architecture switch 502. AT 106 creates anIAM. This IAM can include the calling party's number (if available), thecalled party's number, the point code of AT106 as the OPC, the pointcode of the open architecture switch 502 as the DPC, and the CICrepresenting the bearer channel over link 406 containing the call. TheIAM is sent to the SS7 GW 512, presenting the call on a bearer channelrepresented by another CIC over link 406 to tandem NAS bay 504 (a bearerchannel interface).

[0183] In step 1028, SS7 GW 512 receives signaling information in theIAM message from SS7 network 114, and delivers the information tocontrol server 510. SS7 GW 512 has multiple physical A-link interfacesinto the SS7 network (i.e. preferably one which supports internationalas well as US Domestic SS7 signaling) over which signaling data isreceived. In a preferred embodiment, SS7 GW 512 functionality isimplemented as an application executing on a SUN Microsystemsworkstation model 450, for example, available from Sun Microsystems,Inc. using an SS7 adapter from, for example, DGM&S model Omni 5.0SignalWare, available from DGM&S Telecom, Mount Laurel, N.J. In thispreferred embodiment, SS7 GW 512 and control server 510 are applicationsin communication with one another, running on one or more suchinterconnected host computers. As noted, FIGS. 6 and 7 illustrate oneexample embodiment.

[0184] Referring to FIGS. 6 and 7, these applications are symbolicallyrepresented as OAP SS7 GW application 600 and OAP control serverapplication 700. The communications between SS7 GW 512 and controlserver 510, which together comprise GW 508, were specifically describedwith respect to these figures. SS7 GW 512 parses the IAM message,providing the OPC, DPC, calling party number and called party number,inter alia, to control server 510.

[0185] SS7 GW 512 also functions as a protocol state machine for eachISUP SS7 circuit. In this respect, SS7 GW 512 holds a protocol statemachine for each call that is in process. If SS7 GW 512 does not get aresponse from control server 510 within a certain timeout period, thenit sends a default response out to the SS7 network, which is in thepresent case a release (REL) message. The REL message indicates to homedEO 104 (i.e., via its SSP portion) that the call is to be releasedbecause a timeout occurred. SS7 GW 512 does not necessarily perform therouting itself, but rather communicates with the control server 510which controls the routing functions.

[0186] Referring to FIG. 10C, in step 1030, the control server mustdetermine whether the call is a data call or a voice call to takeappropriate actions. Control server 510 looks up the called party numberin internal or external database 516 to determine whether the call is adata call or a voice call. Based on the type of call, control server 510indicates to control facilities (associated with tandem NAS bay 504) howto route the traffic.

[0187] Control server 510 communicates with the control facilities intandem NAS bay 504 via the open architecture protocol. The controlmessages comprising the protocol are defined in Table 6 generically andin Tables 7-20 in detail. The flows of the control messages, between GW508 (primarily referring to control server 510 in GW 508) and tandem NASbay 504 (primarily referring to control facilities in tandem NAS bay504) are provided in Tables 22-38. For an even more detailed view ofthese flows, the reader is referred to FIG. 11, which illustrates thecontrol facilities of tandem NAS bay 504 (including protocol control1102, call control 1106 and resource management 1104) and GW 508, aswell as FIGS. 13-18B, which provide detailed views of the selectedflows.

[0188] If control server 510 determines the call is a data call, in step1032, it sends a message to the control facilities of tandem NAS bay 504indicating this condition. The tandem NAS bay sends back anacknowledgment. Table 27 illustrates an example message flow for thisstep.

[0189] In step 1034, a data call over a given bearer channel (e.g., aDSO channel) is time division multiplexed by tandem NAS bay 504 fortermination at particular modems. The data call arriving over a givenbearer channel on connection 406 (from AT 106) is assigned to a moduleon modem NAS bay 514. In other words, the incoming bearer channel isassigned to a given bay/module/line/channel (BMLC) going into modem NASbay 514 to a terminating point. Table 32 illustrates an example messageflow for this step.

[0190] In step 1036, a modem performs the conversion (i.e., a modem inmodem NAS bay 514 converts the call from one form into a form suitablefor a destination data network.) For example, the call can be convertedfrom one type of data signal (e.g., a PPP data signal) into another formof data, such as packets (e.g., IP data packets) for routing to anotherpoint such as an ISP. As noted, alternatively, a tunnel can beestablished between the originating caller and the destination datanetwork. Here, a virtual private network, to which the originatingcaller 102 is connected, is extended to the data network.

[0191] Step 1038 is the acceptance of the data call by the platform. Asillustrated in Table 26, a message is sent from the control facilitiesof tandem NAS bay 504 to control server 510, indicating the inbound callis accepted by open architecture platform 402. Control server 510 thenindicates an accepted data connection to SS7 GW 512, which in turn sendsan address complete (ACM) message out over SS7 network 114. When homedEO 104 is made aware of this condition, it plays a ringing signal forcalling party 102, or more specifically, to the modem used by callingparty 102. This indicates a connection is about to be established with amodem.

[0192] In step 1040, the call is connected between a modem on modem NASbay 514 and the modem of calling party 102. As illustrated in Table 27,a message is sent from the control facilities of tandem NAS bay 504 tocontrol server 510, indicating that the inbound call is connected.Control server 510 then indicates a connection indication to SS7 GW 512,which in turn sends an answer (ANM) message over SS7 network 114. Themodem of called party 102 then negotiates with a modem of modem NAS bay514. Here, the name and password of the calling party are verified bythe modem of modem NAS bay 514 via a radius server. The radius serverauthenticates the call, and assigns an IP address from the modem NAS bay514, using the dialed number. The call is routed between calling party102 and another point, such as, an ISP as described with respect to FIG.9A.

[0193] If in step 1030 it is determined that the call is a voice call,the call is transmitted to a voice switch in step 1042. In this case,control server 510 will communicate to tandem NAS bay 504 to transmitthe call to voice switch 506. Voice switch 506 will, in turn, use SS7signaling (via SS7 signaling network 114) to place the call to a calledparty 110. Voice traffic is handled in a conventional manner. In apreferred embodiment, a NORTEL DMS switch, model DMS 500, available fromNORTEL, Richardson, Tex., is used for switching of voice traffic.

[0194] In step 1044, call teardown occurs. For voice traffic effectedbetween calling party 102 and called party 110, teardown occurs usingSS7 signaling in a known manner.

[0195] For teardown of a data call, in a typical scenario, calling party102 initiates the procedure by disconnecting the modem connection. HomedEO 104 sends a release (REL) message, which is transmitted over the SS7signaling network 114 to SS7 GW 512. SS7 GW 512 informs control server510 of the condition. As illustrated in Table 34, control server 510sends a message to the control facilities of tandem NAS bay 504 torelease the call, which sends back an acknowledgment once the call isreleased.

[0196] It should be noted that the functions of SS7 GW 512, controlserver 510 and the NAS bays can all be contained in one collocatedsystem. Many advantages can be achieved, however, by placing thisfunctionality in several devices which can be collocated or placed ingeographically diverse locations. For example, FIG. 9B depicts SS7 GWs512 a, 512 b, and 512 c, connected by multiple links (e.g., A-F links)to SS7 network 114. SS7 GWs 512 a-512 c and CSs 510 a, 510 b, and 510 c,databases 516 a, and 516 b, NASs 902 a, 902 b, 902 c, and 902 d, andinternal backbone 936, can be collocated or geographically diverse. In apreferred embodiment, for high availability, multiple redundantconnections can connect redundant platform resources.

[0197] It should also be noted that the above-noted steps need not beperformed in sequential order. Those skilled in the art will recognizethis fact.

[0198] It would be apparent to a person having skill in the art that theabove is only one implementation of the technology and that multipleimplementations are possible. The reader is referred to the followingtables and FIGS. 11-18B for a more detailed perspective.

3. NAS Bay to GW Communications{TC\l3″}

[0199]FIG. 11 is a block diagram illustrating the functional componentsof NAS bay 902, and how these components communicate with GW 508. Inthis more detailed view, NAS bay 902 includes protocol controlapplication 1102, call control application 1106 and resource managementapplication 1104. Protocol control application 1102 communicates withcall control application 1106 by transmission of primitives. Protocolcontrol application 1102 communicates with resource managementapplication 1104 by the execution of procedure calls. GW 508communicates with NAS bay 902 by the transmission of control messages.These control messages, implemented using the open architecture platformprotocol, are described in detail in the sections below.

[0200]FIG. 12 illustrates a diagram used to show how complex outboundcalls are handled. In these calls, a plurality of NAS bays are involved.Table 35 provides a description that is to be used in concert with FIG.12.

[0201] FIGS. 13-18 provide a series of detailed flow charts (i.e., statediagrams) describing the communications flows between the subcomponentsof NAS bay 902 (including protocol control application 1102, callcontrol application 1106 and resource management application 1104) andGW 508. The state diagrams represent the state of protocol controlapplication 1102 through several processes. The flow charts areexemplary and not exhaustive.

[0202]FIG. 13 depicts an inbound call handling (NAS Side) 1300 statediagram detailing the states of protocol control 1102 during receipt ofan inbound call. Steps 1302 through 1356 outline in detail the stateflow of protocol control 1102 during the call.

[0203]FIGS. 14A and 14B depict NAS side exception handling 1400 statediagrams detailing the states of protocol control 1102 during exceptionhandling. Steps 1402 through 1424 outline in detail the state flow ofprotocol control 1102 during exception handling.

[0204]FIG. 15 depicts a NAS side release request handling 1500 statediagram detailing the states of protocol control 1102 during the processof a release request. Steps 1502 through 1526 outline in detail thestate flow of protocol control 1102 during the release request.

[0205]FIG. 16 depicts a NAS Side TDM connection handling 1600 statediagram detailing the states of protocol control 1102 during the receiptof a TDM call. Steps 1602 through 1630 outline in detail the state flowof protocol control 1102 during the TDM call.

[0206]FIGS. 17A and 17B depict a NAS side continuity test handling 1700state diagram detailing the states of protocol control 1102 duringinitiation of a continuity test. Steps 1702 through 1766 outline indetail the state flow of protocol control 1102 during the test.

[0207]FIGS. 18A and 18B depict a NAS side outbound call handling(initiated by NAS) 1800 state diagram detailing the states of protocolcontrol 1102 during initiation of an outbound call. Steps 1802 through1872 outline in detail the state flow of protocol control 1102 duringthe call. An outbound call is a call initiated from the openarchitecture platform, for security reasons. In response to a call froma calling party, the platform initiates a call to the calling party, andperforms password validation for the call.

4. Control Messages {TC\l3″}

[0208] Table 6 below provides a listing of the names and correspondingcodes for control messages transmitted between GW 508 and NAS bay 902.Also included are the source of each message and the description foreach message. For example, the NSUP message is transmitted from NAS bay902 to GW 508, informing GW 508 that NAS bay 902 is coming up. TABLE 6Name Code Source Description NSUP 0x0081 NAS Notify NAS coming up ASUP0x0082 GW Acknowledgment to NSUP NSDN 0x0083 NAS Notify NAS is about toreboot RST1 0x0085 GW Request system reset - Drop all channels ARST10x0086 NAS Reset in progress - awaiting Reboot command RST2 0x0087 GWRequest system reset (Reboot command) ARST2 0x0088 NAS Rebootacknowledgment MRJ 0x00FF GW or Message reject NAS RSI 0x0091 GW Requestsystem information NSI 0x0092 NAS Response to RSI RBN 0x0093 GW Requestbay number NBN 0x0094 NAS Response to RBN SBN 0x0095 GW Set bay numberABN 0x0096 NAS Acknowledgment to SEN RMI 0x0097 GW Request moduleinformation NMI 0x0098 NAS Notify module information RLI 0x0099 GWRequest line information NLI 0x009A NAS Notify line information RCI0x009B GW Request channel information NCI 0x009C NAS Notify channelinformation SLI 0x009D GW Set line information ASLI 0x009E NASAcknowledgment to SLI RGWI 0x00A1 GW Request Gateway information NGWI0x00A2 NAS Notify Gateway information SGWI 0x00A3 GW Set Gatewayinformation ASGWI 0x00A4 NAS Acknowledgment to SGWI RGWS 0x00A5 GWRequest Gateway status NGWS 0x00A6 NAS Notify Gateway status RMS 0x0041GW Request module status RLS 0x0043 GW Request line status RCS 0x0045 GWRequest channel status NMS 0x0042 NAS Notify module status NLS 0x0044NAS Notify line status NCS 0x0046 NAS Notify channel status SMS 0x0051GW Set a module to a given state SLS 0x0053 GW Set a line to a givenstate SCS 0x0055 GW Set a group of channels to a given state NSCS 0x0056NAS Response to SCS PCT 0x0061 GW Prepare channel for continuity testAPCT 0x0062 NAS Response to PCT SCT 0x0063 GW Start continuity testprocedure with far end as loopback (Generate tone and check for receivedtone) ASCT 0x0064 NAS Continuity test result RTE 0x007D GW or Requesttest NAS echo ARTE 0x007E NAS or Response to GW RTE RTP 0x007B GWRequest test ping to given IP address ATP 0x007C NAS Response to RTF LTN0x0071 GW Listen for DTMF tones ALTN 0x0072 NAS Response to listen forDTMF tones STN 0x0073 GW Send DTMF tones ASTN 0x0074 NAS Completionresult of STN command RCSI 0x0001 GW Request inbound call setup ACSI0x0002 NAS Accept inbound call setup CON1 0x0003 NAS Connect inboundcall (answer) RCSO 0x0005 NAS or Request outbound GW call setup ACSO0x0006 GW or Accept outbound NAS call setup CONO 0x0007 GW or Outboundcall NAS connected RCST 0x0009 GW Request pass- through call setup (TDMconnection between two channels) ACST 0x000A NAS Accept pass- throughcall RCR 0x0011 GW or Release channel NAS request ACR 0x0012 NAS orRelease channel GW complete

5. A Detailed View of the Control Messages{TC\l3″}

[0209] The following section provides a more detailed view of thecontrol messages transmitted between GW 508 and NAS bay 902.

[0210] a. Startup Messages{TC\l4″}

[0211] Table 7 below provides the Startup messages, the parameter tagsand the parameter descriptions (associated with these messages). TABLE 7Startup (registration and de-registration) Parameter Message TagParameter Description NSUP - Notify NAS 0x01 Protocol versionimplemented coming up (initially, set to 0). 0x02 System ID 0x03 Systemtype 0x04 Maximum number of modules (cards) on the system (whetherpresent or not). 0x05 Bay number. ASUP - Acknowledgement 0x02 System IDto NSUP NSDN - Notify NAS 0x02 System ID coming down (about to reboot)RST1 - Request system 0x02 System ID reset - Drop all channels ARST1 -Reset in 0x02 System ID progress - awaiting Reboot command RST2 -Request system 0x02 System ID reset (Reboot command) ARST2 - Reboot 0x02System ID acknowledgment 0x06 Result code: 0x0 Request accepted. NASwill reboot 0 now. 0x0 Request denied. NAS will not 1 reboot.

[0212] b. Protocol Error Messages{TC\l4″}

[0213] Table 8 below provides the Protocol error messages, the parametertags and the parameter descriptions (associated with these messages).TABLE 8 Protocol error handling Parameter Message Tag ParameterDescription MRJ - Message reject 0xFE ISDN cause code

[0214] c. System Configuration Messages{TC\l4″}

[0215] Table 9 below provides the System configuration messages, theparameter tags and the parameter descriptions (associated with thesemessages). TABLE 9 System configuration Parameter Message Tag ParameterDescription RSI - Request system information NSI - Notify system 0x01Protocol version implemented information (initially, set to 0).(response to RSI) 0x02 System ID 0x03 System type 0x04 Maximum number ofmodules (cards) on the system (whether present or not). 0x05 Bay numberThis message is sent as a response to a RSI request. RBN - Request baynumber NBN - Response to RBN 0x05 Bay number This message is sent as aresponse to a RBN request. SBN - Set bay number 0x05 Bay number ASBN -Acknowledgment to 0x05 Bay number SBN This message is sent as a responseto a SBN request.

[0216] d. Telco Interface Configuration Messages{TC \l4″}

[0217] Table 10 below provides the Telco interface configurationmessages, the parameter tags and the parameter descriptions (associatedwith these messages). TABLE 10 Telco interface configuration ParameterMessage Tag Parameter Description RMI—Request 0x07 Module number moduleinformation NMI—Notify 0x07 Module number module 0x0A Module type:information 0x00 not present (response to 0x01 unknown RMI) 0x03 routercard 0x04 8-line channelized T1 0x06 48-modem card 0x07 HDLC card 0x08Ethernet card 0x09 Serial WAN card 0x0A HSSI card 0x0B 10-lineunchannelized T1 0x0D T3 0x0E 48-modem 56K card 0x10 SDSL 0x11 ADSL CAP0x12 ADSL DMT 0x13 standalone modem controller 0x14 32-line IDSL Manyother values are reserved. 0x0B Capabilities/features: logical OR of anyof the following flags: 0x01 Capable of continuity testing 0x02 Networkinterface module 0x08 Number of lines (or items, depending on cardtype). 0x09 External name (i.e., “8t1-card”, etc.) In ASCII format.RLI—Request 0x07 Module number line information information 0x0D Linenumber NLI—Notify 0x07 Module number line 0x0D Line number information0x0E Number of channels (response to 0x0F External name in ASCII formatRLI) 0x10 Line coding: 0x00 Unknown 0x01 AMI D4 AMI 0x02 B8ZS ESF - B8ZS0x11 Framing: 0x00 Unknown 0x01 D4 0x02 ESF 0x12 Signaling type: 0x00Unknown 0x01 In-band 0x02 ISDN PRI 0x03 NFAS 0x04 SS7 gateway 0x13In-band signaling details: 0x00 Unknown 0x01 Wink start 0x02 Idle start0x03 wink-wink with 200 msec wink 0x04 wink-wink with 400 msec wink 0x05loop start CPE 0x06 ground start CPE 0x41 T1 front-end type: 0x00Unknown 0x01 CSU (T1 long haul) 0x02 DSX-1 (T1 short haul) 0x42 T1 CSUbuild-out: 0x00   0 db 0x01  7.5 db 0x02   15 db 0x03 22.5 db 0x43 T1DSX-1 line length: 0x00  1-133 ft 0x01 134-266 ft 0x02 267-399 ft 0x03400-533 ft 0x04 534-655 ft RCI—Request 0x07 Module number Channel 0x0DLine number information 0x15 Channel number NCI—Notify 0x07 Modulenumber channel 0x0D Line number information 0x15 Channel number(response to 0x16 Channel status RCI) 0x17 Bearer Capability of theChannel (BCC) or type of the active call, when a call is present. 0x18Calling Party number 0x19 Dialed Phone number 0x1A Timestamp of the lastchannel status transition SLI—Set line 0x07 Module number information0x0D Line number 0x0F External name in ASCII format 0x10 Line coding:0x01 AMI 0x02 B8ZS 0x11 Framing: 0x01 D4 0x02 ESF 0x12 Signaling type:0x01 In-band 0x02 ISDN PRI 0x03 NFAS 0x04 SS7 gateway 0x13 In-bandsignaling details: 0x01 Wink start 0x02 Idle start 0x03 wink-wink with200 msec wink 0x04 wink-wink with 400 msec wink 0x05 loop start CPE 0x06ground start CPE 0x41 T1 front-end type: 0x01 CSU (T1 long haul) 0x02DSX-1 (T1 short haul) 0x42 T1 CSU build-out: 0x00   0 db 0x01  7.5 db0x02   15 db 0x03 22.5 db 0x43 T1DSX-1 line length: 0x00  1-133 ft 0x01134-266 ft 0x02 267-399 ft 0x03 400-533 ft 0x04 534-655 ft ASLI—New line0x07 Module number information ACK 0x0D Line number

[0218] e. Gateway Configuration Messages{TC\l4″}

[0219] Table 11 below provides the Gateway configuration messages, theparameter tags and the parameter descriptions (associated with thesemessages). TABLE 11 Gateway configuration Parameter Message TagParameter Description RGWI—Request Gateway information NGWI—Notify 0x1BIP Address for Primary gateway Gateway 0x1C TCP port for Primary gatewayinformation 0x1D IP Address for Secondary gateway 0x1E TCP port forSecondary gateway This message is sent as a response to a RGWI request,or when the local NAS configuration is changed by other means. SGWI—Set0x02 Serial Number of Remote Unit Gateway 0x1B New IP Address of Primarygateway information 0x1C TCP port for Primary gateway 0x1D New IPAddress of Secondary gateway 0x1E TCP port for Secondary gateway ASGWI—Acknowledge to SGWI This message is sent as a response to a SGWIrequest. RGWS—Request 0x02 Serial Number of Remote Unit Gateway statusNGWS—Notify 0x02 Serial Number of Remote Unit Gateway 0x1B New IPAddress of Primary Host status 0x1C TCP port for Primary 0x1D New IPAddress of Secondary Host 0x1E TCP port for Secondary 0x1F Gateway inuse (Primary/Secondary) This message is sent as a response to a RGWSrequest.

[0220] f. Maintenance-Status (State) Messages{TC\l4″}

[0221] Table 12 below provides the Maintenance-Status (State) messages,the parameter tags and the parameter descriptions (associated with thesemessages). TABLE 12 Maintenance - Status (State) Parameter Message TagParameter Description RMS—Request module 0x07 Module number status Thismessage will force an immediate NMS. RLS—Request line 0x07 Module numberstatus 0x0D Line number This message will force an immediate NLS.RCS—Request channel 0x07 Module number status 0x0D Line number 0x15Channel number This message will force an immediate NCS. NMS—Notifymodule 0x07 Module number status 0x0A Module type (see NMI above) 0x0CModule status 0x20 Number of lines (for network interface modules only)0x21 Line status: one entry per line (for network interface modulesonly) This message should be issued by the NAS any time that the modulestatus changes or if a RMS command was received. NLS—Notify line status0x07 Module number 0x0D Line number 0x14 Line status 0x22 Number ofchannels 0x23 Channel status: one entry per channel This message shouldbe issued by the NAS any time that the line status changes or if a RLScommand was received. NCS—Notify channel 0x07 Module number status 0x0DLine number 0x15 Channel number 0x16 Channel status This message shouldbe issued by the NAS if an RCS command was received. SMS—Set a module toa 0x07 Module number given status 0x24 Requested state: 0x00 out ofservice 0x01 initialize (bring up) As the Module changes status, the NASwill notify the GW with NMS messages. The correlator in those NMSmessages will not be the same as the correlator in the SMS message.SLS—Set a line to a 0x07 Module number given status 0x0D Line number0x25 Requested state: 0x00 Disable 0x01 Enable 0x02 Start loopback 0x03Terminate loopback As the line changes status, the NAS will notify theGW with NLS messages. The correlator in those NLS messages will not bethe same as the correlator in the SLS message. SCS—Set a group of 0x07Module number channels to a given status 0x0D Line number 0x28 StartChannel number 0x29 End Channel number 0x26 Action: 0x00 Reset to idle0x01 Reset to out of service 0x02 Start loopback 0x03 Terminate loopback0x04 Block 0x05 Unblock 0x27 Option: 0x00 Do not perform the indicatedaction if any of the channels is not in the valid initial state. 0x01Perform the indicated action on channels which are on the valid initialstate. Other channels are not affected. Action Valid initial state Finalstate Reset to idle maintenance, blocked, loopback, idle, idle in use,conected Reset to out of maintenance, blocked, loopback, idle, out ofservice service in use, connected Start loopback idle loopback Endloopback loopback idle Block idle blocked Unblock blocked idleNSCS—Response to 0x07 Module number SCS 0x0D Line number 0x28 StartChannel number 0x29 End Channel number 0x2A Response code: 0x00 actionsuccessfully performed in all channels 0x01 at least one channel failed0x22 Number of channels 0x23 Channel status: one entry per channel

[0222] g. Continuity Test Messages{TC\l4″}

[0223] Table 13 below provides the Continuity test messages, theparameter tags and the parameter descriptions (associated with thesemessages). TABLE 13 Continuity test Parameter Message Tag ParameterDescription PCT—Prepare channel 0x07 Module number for continuity test0x0D Line number 0x15 Channel number APCT—Response to 0x07 Module numberPCT request 0x0D Line number 0x15 Channel number 0x2B Result: 0x00Resources reserved successfully 0x01 Resource not available SCT—Startcontinuity 0x07 Module number test procedure with far 0x0D Line numberend as loopback 0x15 Channel number 0x2C Timeout in milliseconds.Default is 2 seconds. The SCT command must be received less than 3seconds after the APCT was sent. The continuity test performed by theNAS is as follows: 1. Start tone detection 2. Generate a check tone 3.Start timer 4. When tone is detected (minimum of 60 ms): 4.1. Stoptimer. 4.2. Stop generator 4.2.1. TEST SUCCESSFUL 5. If timer expires:5.1. Stop generator 5.2. TEST FAILED After continuity testing, a channelis always left in the idle state. ASCT—Continuity test 0x07 Modulenumber result 0x0D Line Number 0x15 Channel Number 0x2D Result: 0x00Test completed successfully 0x01 Test failed

[0224] h. Keepalive Test Messages{TC\l4″}

[0225] Table 14 below provides the Keepalive test messages, theparameter tags and the parameter descriptions (associated with thesemessages). TABLE 14 Keepalive test Parameter Message Tag ParameterDescription RTE—Request test echo 0x2E Random characters ARTE—Responseto 0x2E Same random characters from RTE RTE

[0226] i. LAN Test Messages{TC\l4″}

[0227] Table 15 below provides the LAN test messages, the parameter tagsand the parameter descriptions (associated with these messages). TABLE15 LAN test Parameter Message Tag Parameter Description RTF—Request atest 0x02 System ID ping 0x2F IP Address to Ping 0x30 Number of pings tosend ATP—Response to RTF 0x02 System ID 0x2F IP Address to Ping 0x30Number of successful pings

[0228] j. DTMF Function Messages{TC\l4″}

[0229] Table 16 below provides the DTMF function messages, the parametertags and the parameter descriptions (associated with these messages).TABLE 16 DTMF functions Parameter Message Tag Parameter Description LTN—0x07 Module number Listen 0x0D Line number for DTMF 0x15 Channel numbertones 0x31 Time to wait for a tone (since either last tone heard orstart of command) - in milliseconds 0x32 Maximum number of tones torecognize 0x34 Tone to cancel the wait If resources are available, theNAS starts listening for DTMF tones on the given channel. The procedureis as follows: 1. Starts timer. 2. When a tone is recognized: 2.1.Restart timer. 2.2. If the recognized tone is the ‘tone to cancel’, theoperation is concluded and a response is generated (cancel tonereceived). 2.3. Add the tone to the response string. If the number oftones on the string exceeds the maximum allowed, the operation isconcluded and a response is generated (max tones received). 2.4. Whenthe tone is removed, restart the timer and continue from step 2. 2.5. Ifthe timer expires, the operation is concluded and a response isgenerated (tone too long). 3. If the timer expires, the operation isconcluded and a response is generated (timeout). ALTN— 0x07 Modulenumber Response 0x0D Line number to LTN 0x15 Channel number 0x35Completion status: 0x00 Timeout 0x01 No resources available for thisoperation 0x02 Operation was interrupted 0x03 Cancel tone received 0x04Maximum tones received 0x05 Tone too long 0x32 Number of tones received0x33 String of tones received (ASCII characters ‘0’-‘9’, ‘*’, ‘#’)STN—Send 0x07 Module number DTMF tones 0x0D Line number 0x15 Channelnumber 0x32 Number of tones to send 0x33 String of Tones to send (ASCIIcharacters ‘0’-‘9’, ‘*’, ‘#’, ‘d’ - contiguous dialtone, ‘b’ -contiguous user busy, ‘n’ - contiguous network busy, ‘s’ - short pause,‘r’ - contiguous ringback) ASTN— 0x07 Module number Completion 0x0D Linenumber result of 0x15 Channel number STN command 0x36 Completion status:0x00 Operation succeeded 0x01 Operation failed 0x02 Operation wasinterrupted

[0230] k. Inbound Call Handling Messages{TC\l4″}

[0231] Table 17 below provides the Inbound call handling messages, theparameter tags and the parameter descriptions (associated with thesemessages). TABLE 17 Inbound call handling Parameter Message TagParameter Description RCSI—Request 0x07 Module number inbound 0x0D Linenumber call setup 0x15 Channel number 0x17 Bearer Capability of theChannel (BCC) required for the call. 0x19 Called Phone number 0x18Calling Party number This message is a notification from the GW to theNAS that an inbound call is pending. The NAS should respond with an ACSImessage indicating if it accepts or with an ACR if it rejects the call.The valid channel states for this command are idle or loopback. If thechannel is in loopback state, loopback mode is ended and the callproceeds. ACSI—Accept 0x07 Module number inbound 0x0D Line number callsetup 0x15 Channel number This message is a notification from the NAS tothe GW that an inbound call has been accepted. Appropriate resourceshave been reserved at the NAS for this call. CONI—Connect 0x07 Modulenumber inbound 0x0D Line number call (answer) 0x15 Channel number 0x40Call identifier assigned by the NAS This message is an indication fromthe NAS to the GW to answer an inbound call.

[0232] l. Outbound Call Handling Messages{TC\l4″}

[0233] Table 18 below provides the Outbound call handling messages, theparameter tags and the parameter descriptions (associated with thesemessages). Outbound call handling Parameter Message Tag ParameterDescription RCSO— 0x07 Module number Request 0x0D Line number outbound0x15 Channel number call setup 0x17 Bearer Capability of the Channel(BCC) required for the call. 0x19 Called Phone number¹ 0x18 CallingParty number¹ 0x37 Destination module² 0x38 Destination line² 0x39Destination channel² 0x40 Call identifier assigned by the NAS³ If thecall is initiated by the NAS, the Module, Line and Channel numbers areset to 0, because it is up to the GW to assign an appropriate channelfor the outgoing call. If the call is initiated by the GW, the Module,Line and Channel numbers indicate the channel that should be connectedto the outbound call. The NAS will place a call in one of its regulartrunks (such as an ISDN PRI line). The GW or the NAS will respond with aACSO (if the call was accepted) or with a RCR (if the call wasrejected). When the outbound call is established, it will be connectedto the channel specified by the tags 0x07/0x0D/0x15. ACSO—Accept 0x07Module number outbound call setup 0x0D Line number 0x15 Channel numberIf the call was initiated by the NAS, this is a notification from the GWthat an outbound call was accepted and it is pending. The Gateway shouldsend an RCR message if it wants to reject a call. If the call wasinitiated by the GW, this is a notification from the NAS that anoutbound call was accepted and it is pending. The NAS would have sent anRCR message if it wanted to reject a call.

[0234] TABLE 18 Outbound call handling Parameter Message Tag ParameterDescription CONO—Outbound call 0x07 Module number connected 0x0D Linenumber 0x15 Channel number 0x40 Call identifier assigned by the NAS.⁴This message is a notification from the GW to the NAS that an outboundcall has been connected.

[0235] m. Pass-through Call Handling Messages{TC\l4″}

[0236] Table 19 below provides the Pass-through call handling messages,the parameter tags and the parameter descriptions (associated with thesemessages). TABLE 19 Pass-through call handling Parameter Message TagParameter Description RCST—Request pass- 0x07 From Module number throughcall setup (TDM 0x0D From Line number connection between two 0x15 FromChannel number channels) 0x17 Bearer Capability of the Channel (BCC)required for the call. 0x37 To Module number 0x38 To Line number 0x39 ToChannel number This message is a request from the GW to the NAS to linktwo channels. The NAS should respond with an ACST if it accepts theconnection or with a RCR if it rejects the connection. The indicatedchannels are interconnected at the time slot level. The NAS will notperform any rate adaptation. It is the Gateway's responsibility tospecify compatible channels. ACST—Accept pass- 0x07 From Module numberthrough call 0x0D From Line number 0x15 From Channel number 0x37 ToModule number 0x38 To Line number 0x39 To Channel number This message isa notification from the NAS to the GW that a TDM connection has beenaccepted and connected. The two indicated channels are now connected.

[0237]

[0238] n. Call Clearing Messages{TC\l4″}

[0239] Table 20 below provides the Call clearing messages, the parametertags and the parameter descriptions (associated with these messages).TABLE 20 Call clearing Parameter Message Tag Parameter DescriptionRCR—Release 0x07 Module number channel request 0x0D Line number 0x15Channel number 0xFE ISDN cause code In the case of a pass-through call(TDM connection), the channel identified should be the ‘from’ side.ACR—Release 0x07 Module number channel completed 0x0D Line number 0x15Channel number 0xFE ISDN cause code

6. Control Message Parameters{TC\l4″}

[0240] Table 21 below provides a listing of the control messageparameters, and the control messages which use these message parameters.More specifically, Table 21 provides the tags associated with theparameters, the size (in bytes) of the parameters, the type of theparameters (e.g., ASCII), the parameter descriptions, and the controlmessages which use the parameters. TABLE 21 Size Tag (bytes) TypeParameter description Usage 0x00 0 End marker All messages. 0x01 1 UINTProtocol version NSUP 0x02 1 to 24 ASCII System ID/Serial Number NUSP,ASUP, NSDN, RST1, ARST1, RST2, ARST2, NSI, SGWI, ROWS, NGWS 0x03 9 ASCIISystem type NSUP, NSI 0x04 2 UINT Max. number of modules NSUP, NSI (slotcards) supported 0x05 8 Bay number NSUP, NSI, NBN 0x06 1 Rebootacknowledgment ARST2 0x07 2 UINT Module number RMI, NMI, RLI, NLI, RCI,NCI, SLI, ASLI, RMS, RLS, RCS, NMS, NLS, NCS, SMS, SLS, SCS, NSCS, PCT,APCT, SCT, ASCT, LTN, ALTN, STN, ASTN, RCSI, ACSI, CONI, RCSO, ACSO,CONO, RCST, ACST, RCR, ACR 0x08 2 UINT Number of lines on this NMI, NMSmodule 0x09 16 ASCII Module name NMI 0x0A 1 Module type NMI 0x0B 1Module capabilities NMI 0x0C 1 Module Module status NMS Status 0x0D 2UINT Line number RLI, NLI, RCI, NCI, SLI, ASLI, RLS, RCS, NLS, NCS, SLS,SCS, NSCS, PCT, APCT, SCT, ASCT, LTN, ALTN, STN, ASTN, RCSI, ACSI, CONI,RCSO, ACSO, CONO, RCST, ACST, RCR, ACR 0x0E 2 UINT Number of channels onNLI, NLS this line 0x0F 16 ASCII Line name NLI, SLI 0x10 1 Line codingNLI, SLI 0x11 1 Line framing NLI, SLI 0x12 1 Line signaling details NLI,SLI 0x13 1 Line in-band signaling NLI, SLI details 0x14 1 Line Linestatus NLS Status 0x15 2 UINT Channel number RCI, NCI, RCS, NCS, SCS,NSCS, PCT, APCT, SCT, ASCT, LTN, ALTN, STN, ASTN, RCSI, ACSI, CONI,RCSO, ACSO, CONO, RCST, ACST, RCR, ACR 0x16 1 Channel Channel status NCSStatus 0x17 1 Bearer capability NCI, RCSI, RCSO, RCST 0x18 24 ASCIICalling party number NCI, RCSI, RCSO 0x19 24 ASCII Dialed number NCI,RCSI, RCSO 0x1A 4 TIME Channel status change NCI timestamp 0x1B 4 IpaddrPrimary Gateway IP NGWI, SGWI, NGWS 0x1C 2 UINT Primary Gateway TCP portNGWI, SGWI, NGWS 0x1D 4 Ipaddr Secondary Gateway IP NGWI, SGWI, NGWS0x1E 2 UINT Secondary Gateway TCP NGWI, SGWI, NGWS port 0x1F 1 Gatewayselector NGWS 0x20 2 UINT Number of lines in the NMS Line status array0x21 Variable Line Line status array NMS Status 0x22 2 UINT Number ofchannels in the NLS Channel status array 0x23 Variable Channel Channelstatus array NLS Status 0x24 1 Requested module state SMS 0x25 1Requested line state SLS 0x26 1 Requested channel status SCS 0x27 1 Setchannel status option SCS 0x28 2 UINT Channel number first (for SCS,NSCS grouping) 0x29 2 UINT Channel number last (for SCS, NSCS grouping)0x2A 1 “Set channel status” result NSCS 0x2B 1 “Prepare for continuityAPCT check” result 0x2C 2 UINT Continuity timeout SCT 0x2D 1 Continuitytest result ASCT 0x2E 0 to 16 Test echo RTE, ARTE 0x2F 4 Ipaddr Testping address RTF, ATP 0x30 2 UINT Test ping: Number of RTF, ATP packets0x31 2 UINT DTMF listen time LTN 0x32 1 UINT DTMF number of tones LTN,ALTN, STN 0x33 Variable ASCII DTMF string (‘0’-‘9’, ‘A’- ALTN, STN ‘D’,‘*’, ‘#’) 0x34 1 BYTE DTMF tone to cancel the LTN waiting 0x35 1 DTMFlisten completion ALTN status 0x36 1 DTMF send completion STN status0x37 2 UINT TDM destination Module RCST, ACST, RCSO (gw) 0x38 2 UINT TDMdestination Line RCST, ACST, RCSO (gw) 0x39 2 UINT TDM destinationchannel RCST, ACST, RCSO (gw) 0x40 2 UINT Call identifier (RAS's CONI,CONO, RCSO (nas) Route ID) 0x41 1 BYTE T1 front-end type SLI, NLI 0x42 1BYTE T1 CSU build-out SLI, NLI 0x43 1 BYTE T1 DSX line length SLI, NLI0xFE 1 UINT ISDN cause code RCR, ACR, others

7. A Detailed View of the Control Messages{TC\l3″}

[0241] The following section provides a detailed view of the flow ofcontrol messages between GW 508 and NAS bay 902. Included are the source(either GW 508 or NAS bay 902) and relevant comments describing themessage flow.

[0242] a. Startup Flow {TC\l4″}

[0243] Table 22 below provides the Startup flow, including the step, thecontrol message source (either GW 508 or NAS bay 902) and relevantcomments. TABLE 22 Step Gateway NAS Comments 1 NSUP NAS coming up. Themessage contains server information, including number of modules in thesystem. 2 ASUP

[0244] b. Module Status Notification {TC\l4″}

[0245] Table 23 below provides the Module status notification flow,including the step, the control message source (either GW 508 or NAS bay902) and relevant comments. TABLE 23 Step Gateway NAS Comments 1 NMSNotify module status. 2 If the module is in the UP state: 3 RMI Requestmodule information 4 NMI Notify module information (including number oflines in this module).

[0246] c. Line Status Notification Flow{TC\l4″}

[0247] Table 24 below provides the Line status notification flow,including the step, the control message source (either GW 508 or NAS bay902) and relevant comments. TABLE 24 Step Gateway NAS Comments 1 NLSNotify line status. 2 If the line is in the UP state: 3 RLI Request lineinformation 4 NLI Notify line information (including number ofchannels).

[0248] Note: Channels will remain in the our-of-service state until theline becomes available. At that time, the channels will be set to theidle state. The Gateway must then explicitly disable or block channelsthat should not be in the idle state.

[0249] d. Blocking of Channels Flow{TC\l4″}

[0250] Table 25 below provides the Blocking of channels flow, includingthe step, the control message source (either GW 508 or NAS bay 902) andrelevant comments. TABLE 25 Step Gateway NAS Comments 1 SCS Set a groupof channels to be blocked state. 2 RSCS Message indicates if theoperation was successful or if it failed.

[0251] e. Unblocking of Channels Flow{TC\l4″}

[0252] Table 26 below provides the Unblocking of channels flow,including the step, the control message source (either GW 508 or NAS bay902) and relevant comments. TABLE 26 Step Gateway NAS Comments 1 SCS Seta group of channels to be unblocked state. 2 RSCS Message indicates ifthe operation was successful or if it failed.

[0253] f. Inbound Call Flow (Without Loopback ContinuityTesting){TC\l4″}

[0254] Table 27 below provides the Inbound call flow (without loopbackcontinuity testing), including the step, the control message source(either GW 508 or NAS bay 902) and relevant comments. TABLE 27 StepGateway NAS Comments 1 RCSI Setup for inbound call on givenmodule/line/channel 2 ACSI Accept inbound call. At this time, the NASmay start any Radius lookup, etc. 3 CONI Connect (answer) inbound call.

[0255] g. Inbound Call Flow (With Loopback Continuity Testing){TC\l4″}

[0256] Table 28 below provides the Inbound call flow (without loopbackcontinuity testing), including the step, the control message source(either GW 508 or NAS bay 902) and relevant comments. TABLE 28 StepGateway NAS Comments 1 SCS Set a channel to the loopback state. 2 RSCSMessage indicates if the operation was successful or if it failed. 3 Ifthe gateway determines that the test was successful: 3.1 RCSI Setup forinbound call on given module/line/channel. 3.2 ACSI Accept/Rejectinbound call. At this time, the NAS may start any Radius lookup, etc.3.3 CONI Connect (answer) inbound call. 4 If the gateway determines thatthe test was not successful: 4.1 SCS Release a channel from the loopbackstate (back to idle state) 4.2 RSCS Message indicates if the operationwas successful or if it failed.

[0257] h. Outbound Call Flow (Starting from the NAS){TC\l4″}

[0258] Table 29 below provides the Outbound call flow (starting from theNAS), including the step, the control message source (either GW 508 orNAS bay 902) and relevant comments. TABLE 29 Step Gateway NAS Comments 1RCSO Request outbound call. Note that the NAS doesn't know yet whatmodule/ line/channel will be used for the call and so, they are set to0. 2 ACSO Accept/Reject outbound call on module/line/channel. Thismessage is used by the Gateway to notify the NAS whichmodule/line/channel will be used for the call. If the NAS can't processthe call on that channel, it should issue a Release command. 3 CONOOutbound call answered by called party.

[0259] i. Outbound Call Flow (Starting from the GW){TC\l4″}

[0260] Table 30 below provides the Outbound call flow (starting from theGW), including the step, the control message source (either GW 508 orNAS bay 902) and relevant comments. TABLE 30 Step Gateway NAS Comments 1RCSO Request outbound call. The Gateway indicates the channel thatshould be connected to the outbound call. 2 ACSO Accept/Reject outboundcall on module/line/channel. The NAS will place the call using one ofthe interfaces (such as an ISDN PRI line). 3 CONO Outbound call answeredby called party. The pass-through connection is established.

[0261] j. Outbound Call Flow (Starting from the NAS, with ContinuityTesting){TC\l4″}

[0262] Table 31 below provides the Outbound call flow (starting from theNAS, with continuity testing), including the step, the control messagesource (either GW 508 or NAS bay 902) and relevant comments. TABLE 31Step Gateway NAS Comments 1 RCSO Request outbound call. Note that theNAS doesn't know yet what module/ line/channel will be used for the calland so, they are set to 0. 2 The Gateway requests a continuity test: 2.1RPCT Prepare for Continuity test 2.2 APCT Accept continuity test 2.3 SCTStart continuity test. If the NAS doesn't receive this command within 3seconds of sending an APCT, the continuity test will be canceled and allreserved resources will be released. 2.4 ASCT Continuity test result. 3ACSO Accept outbound call on module/line/ channel. This message is usedby the Gateway to notify the NAS which module, line and channel will beused for the call. If the NAS can't process the call on that channel, itshould issue a Release command. 4 CONO Outbound call answered by calledparty.

[0263] k. TDM Pass-through Call Request Flow (InterswitchConnection){TC\l4″}

[0264] Table 32 below provides the TDM pass-through call request flow(inter-switch connection), including the step, the control messagesource (either GW 508 or NAS bay 902) and relevant comments. TABLE 32Step Gateway NAS Comments 1 RCST Gateway requests a given pair ofmodule/line/channel to be interconnected for inter-trunk switching. 2ACST Accept/Reject inter-trunk switch connection.

[0265] l. Call Releasing Flow (from NAS){TC\l4″}

[0266] Table 33 below provides the Call releasing flow (from NAS),including the step, the control message source (either GW 508 or NAS bay902) and relevant comments. TABLE 33 Step Gateway NAS Comments 1 RCR NASneeds to release a call (for example, it received an LCP TRMREQ). 2 ACRWhen Gateway completes the release, it notifies the NAS.

[0267] m. Call Releasing Flow (from GW){TC\l4″}

[0268] Table 34 below provides the call releasing flow (from GW),including the step, the control message source (either GW 508 or NAS bay902) and relevant comments. TABLE 34 Step Gateway NAS Comments 1 RCRGateway requests to release a call (for example, the remote end hungup). 2 ACR When the NAS completes the release, it notifies the Gateway.

[0269] n. Complex Outbound Call Request Flow Example{TC\l4″}

[0270] Table 35 below provides an Complex outbound call request flowexample, including the step, the control message source (either GW 508or NAS bay 902) and relevant comments. The reader is referred to FIG. 12for an illustration and state flow diagrams 18A and 18B. TABLE 35 StepFrom To Message Comments NAS#1 GW RCSO NAS#1 requests an outbound call.Gateway determines that the best route to destination is through a PRIline on NAS#3. To get there, it will use NAS#2 as a switch point. TheGateway selects channel 1/2/3 on NAS#1 for this call. GW NAS#2 RCSTGateway asks NAS#2 to establish a TDM connection between channel 2/3/3and channel 4/5/6. NAS#2 GW ACST NAS#2 accepts and connects theconnection. GW NAS#3 RCSO Gateway asks NAS#3 to place a call to thedestination and connect it to the channel 6/7/6. NAS#3 GW ACSO NAS#3accepts the outbound connection and starts setting up the outbound callon PRI #1. GW NAS#1 ACSO Gateway tells NAS#1 that the call isproceeding. NAS#3 GW CONO NAS#3 reports the outbound call has beenconnected. GW NAS#1 CONO The call has been connected.

[0271] o. Continuity Test Flow{TC\l4″}

[0272] Table 36 below provides the Continuity test flow, including thestep, the control message source (either GW 508 or NAS bay 902) andrelevant comments. TABLE 36 Step Gateway NAS Comments 1 RPCT Prepare forcontinuity test. 2 APCT Accept continuity test. 3 SCT Start continuitytest. If the NAS doesn't receive this command within 3 seconds ofsending an APCT, the continuity test will be canceled and all reservedresources will be released. 4 ASCT Continuity test result.

[0273] p. Keep-alive Test Flow{TC\l4″}

[0274] Table 37 below provides the Keep-alive test flow, including thestep, the control message source (either GW 508 or NAS bay 902) andrelevant comments. TABLE 37 Step Gateway NAS Comments 1 RTE Responsetest echo is sent. 2 ARTE A response to test echo is sent.

[0275] q. Reset Request Flow{TC\l4″}

[0276] Table 38 below provides the Reset request flow, including thestep, the control message source (either GW 508 or NAS bay 902) andrelevant comments. TABLE 38 Step Gateway NAS Comments 1 RST1 First step.2 ARST1 3 RST2 Second step. If the NAS doesn't receive this commandwithin 5 seconds of sending an ARST1, it will not reboot. 4 ARST2 TheNAS starts the reboot procedure. 5 NSDN NAS is now rebooting.

[0277] V. Conclusion{TC\l1″}

[0278] While various embodiments of the present invention have beendescribed above, it should be understood that they have been presentedby way of example only, and not limitation. Thus, the breadth and scopeof the present invention should not be limited by any of theabove-described exemplary embodiments, but should be defined only inaccordance with the following claims and their equivalents.

What is claimed is:
 1. A system for bypassing the egress facilities of atelecommunications system, the system comprising: (i) a gateway forcommunicating with a telecommunications carrier by receiving andtransmitting signaling messages; (ii) a network access server forterminating data calls and for termination and reorigination processingof said data calls; and (iii) a control server for communicating withsaid gateway, for distinguishing between voice calls and said data callsreceived from said telecommunications carrier, and for sending said datacalls to said network access server.
 2. The system according to claim 1,wherein said signaling messages are SS7 signaling messages, and whereinsaid gateway is an SS7 gateway device.
 3. The system according to claim1, wherein said gateway communicates with a switch facility in saidtelecommunications carrier via said signaling messages.
 4. The systemaccording to claim 3, wherein said switch facility is one of: a class ¾access tandem switch; and a class 5 end office switch.
 5. The systemaccording to claim 1, wherein said gateway is a first applicationprogram running on a host computer, said control server being a secondapplication program running on said host computer or on a second hostcomputer, and said first application program and said second applicationprogram intercommunicate.
 6. The system according to claim 1, whereinsaid control server comprises a communications portion for communicatingwith said gateway.
 7. The system according to claim 6, wherein saidcommunications portion of said control server and said gatewaycommunicate via one of: X.25 protocol format; transmission controlprogram, internet protocol (TCP/IP) packet format; and user datagramprotocol, internet protocol (UDP/IP) packet format.
 8. The systemaccording to claim 1, wherein said control server comprises acommunications portion for communicating with a communications portionof said network access server.
 9. The system according to claim 8,wherein said data calls have a digitized data format, said digitizedformat contains one of: a cell, a packet, and a frame.
 10. The systemaccording to claim 1, wherein said network access server comprises asecond device which can be used to time division multiplex switch saiddata calls to another network access server.
 11. The system according toclaim 19, wherein said second device comprises a tandem network accessserver bay.
 12. The system according to claim 1, said control servercomprises: a database for distinguishing between said voice calls andsaid data calls; and said database includes a table comprising calledparty number sand terminating points associated with said called partynumbers.
 13. The system according to claim 12, wherein said controlserver determines that if said called party number is associated with adata modem, then a call received is one of said data calls.
 14. Thesystem according to claim 1, further comprising: a voice switch forswitching said voice calls and for transmitting said voice calls fromthe system.
 15. The system according to claim 1, wherein the system isan open architecture platform.
 16. The system according to claim 15,wherein said open architecture platform is integrated into facilitiesof: an incumbent local exchange carrier (ILEC), an interexchange carrier(IXC), a competitive local exchange carrier (CLEC), and an enhancedservices provider.
 17. The system according to claim 1, wherein anycombination of said gateway, said control server and said network accessserver are collocated.
 18. The system according to claim 1, wherein anycombination of said gateway, said control server and said network accessserver are located geographically apart from one another.
 19. The systemaccording to claim 14, wherein any combination of said gateway, saidcontrol server, said network access server and said voice switch arecollocated.
 20. The system according to claim 14, wherein anycombination of said gateway, said control server, said network accessserver and said voice switch are located geographically apart from oneanother.
 21. A system for bypassing the egress facilities of atelecommunications system, the system comprising: (a) a voice switchtransmitting voice calls to a called party; and (b) an open architectureswitch receiving data calls and said voice calls from atelecommunications carrier, said open architecture switch including (i)a modem network access server terminating said data calls to a modem;(ii) a tandem network access server receiving said data calls and saidvoice calls; and (iii) a gateway including a gateway signalling systemmanaging signaling information for said open architecture switch, and acontrol server capable of controlling said modem network access serverand said tandem network access server, wherein said control server iscapable of distinguishing between said data calls and said voice calls,transmitting said voice calls to said voice switch, and transmittingsaid data calls to said modem network access server.
 22. A system forbypassing the egress facilities of a telecommunications carrier,comprising: means for receiving and distinguishing between data callsand voice calls; and means for converting said data calls into a formused by a data network.
 23. The system according to claim 22, wherein:said converting means comprises at least one network access server forterminating said incoming data calls to modems, wherein said modemsconvert said incoming data calls from a first format to a second format;and said receiving and distinguishing means comprises a gateway forhandling signaling information, and a control server for controllingsaid gateway and said at least one network access server.
 24. The systemaccording to claim 22, wherein said converting means comprises: anetwork access server for terminating said incoming data calls tomodems, wherein said modems convert said incoming data calls from afirst format to a second format.
 25. The system according to claim 22,wherein said system further comprises: a voice switch for switching saidvoice calls.
 26. A method for bypassing data from egress facilities of atelecommunications carrier, the method comprising the steps of:establishing a call with an open architecture telecommunications system;determining whether said call is a voice call or a data call; andterminating said call onto a network access server for terminationprocessing, if said call is a data call.
 27. The method according toclaim , wherein said step of establishing a call with saidtelecommunications system comprises: receiving signaling information toset up a call coming into said open architecture telecommunicationssystem; informing a control server that a call has arrived on said openarchitecture telecommunications system; and receiving said call at saidopen architecture telecommunications system.
 28. The method according toclaim 27, wherein said step of receiving signaling information comprisesreceiving signaling information at a gateway.
 29. The method accordingto claim 28, wherein signaling system 7 (SS7) signaling information isreceived at said gateway.
 30. The method according to claim 28, whereinsaid gateway is an application program running on a host computer. 31.The method according to claim 26, wherein said determining step isperformed by a control server.
 32. The method according to claim 31,wherein said control server is an application program running on a hostcomputer.
 33. The method according to claim 26, wherein said determiningstep comprises: using a telephone number of a called party to determinewhether said call is a voice call or a data call.
 34. The methodaccording to claim 33, wherein said telephone number is a number used toaccess one of: at least one network device of an Internet ServicesProvider (ISP); at least one network device of a competitive localexchange (CLEC) carrier; at least one network device of an incumbentlocal exchange (ILEC) carrier; at least one network device of anenhanced services provider (ESP); at least one Intelligent Peripheral(IP) network device; and at least one customer premises equipment (CPE).35. The method according to claim 33, wherein said using step comprises:looking up said telephone number in a database.
 36. The method accordingto claim 26, wherein said terminating step comprises: providing aprotocol tunnel from a first network to a second network.
 37. The methodaccording to claim 36, comprising: using a virtual private networkprotocol to extend said first network to said second network.
 38. Themethod according to claim 37, wherein said virtual private networkprotocol comprises a point-to-point tunneling (PPTP) protocol.
 39. Themethod according to claim 37, wherein said first network is a virtualprivate network, and wherein said second network is a data network. 40.The method according to claim 26, wherein said call is terminated ontoat least one modem in said network access server.
 41. The methodaccording to claim 40, wherein said call and at least one other callterminated at said network access server are connected in a timedivision multiplexed switching connection to said at least one modem.42. The method according to claim 26, wherein said terminating stepcomprises: terminating said call to a voice switch, if said call is avoice call.
 43. A method for bypassing data from the facilities of atelecommunications carrier comprising the steps of: (a) receivingsignaling information for transmitting a call; (b) converting saidsignaling information into a format used by an open architectureplatform; (c) receiving said call on said platform; (d) determiningwhether said call is a voice call or a data call; (e) controlling atleast one network access server; (f) terminating said call in said atleast one network access server, if said call is a data call; and (g)transmitting said call to a voice switch, if said call is a voice call.44. The method according to claim 43, wherein step (f) comprises one of:(i) terminating said call to a modem; and (ii) establishing a tunnel toa virtual private data network.
 45. The method according to claim 44,wherein step (ii) comprises: uses a point-to-point tunneling protocol(PPTP) to extend a virtual private network to a second network.
 46. Abypass system receiving telecommunications traffic including voicetraffic and data traffic from a telecommunications carrier and bypassingthe data traffic around egress facilities of the telecommunicationscarrier, said bypass system comprising: one or more network accessservers receiving said telecommunications traffic and separately routingthe voice traffic and data traffic; one or more gateways exchangingmessages with the telecommunications carrier and providing signalinginformation to one or more control servers; said one or more controlservers responsive to said signaling information and detecting whetherdata traffic or voice traffic is being received by a network accessserver associated with the signaling information, and sending routingcontrol information to the network access server receiving thetelecommunications traffic associated with the signaling information;and said network access server associated with the signaling informationtransmitting voice traffic to a voice switch if the telecommunicationstraffic is voice traffic and converting the telecommunications trafficto a form suitable for a destination data network if thetelecommunications traffic is data traffic.
 47. The bypass system ofclaim 46 where there are plurality of network access servers shared byone or more control servers.
 48. The bypass system of claim 47 wheresaid network access servers are located at geographically diverselocations remote from said one or more control servers and are connectedto said one or more control servers through communication links.
 49. Thebypass system of claim 47 where the transmitting and convertingfunctions of said network access servers are distributed across aplurality of network access servers at locations remote from said one ormore control servers connected to said network access servers through acommunication network.
 50. The bypass system of claim 46 where there area plurality of control servers shared by a plurality of gateways.